Reverse zones: name hosts from other views' records; search and bulk dismiss for long lists

A reverse zone's fill (and fill-ptr, the missing-PTR counts) names an address no record of its own view uses from another view's record, so an internal reverse zone can give the PTR of a host only external has an AAAA for; New reverse zone with a view chosen lists those addresses, marked. Automatic suggestions stay per view.

For hundreds of addresses: the New reverse zone list has a search; on the Zones page the public addresses fold away, have a search, show 25 at a time and Dismiss these N dismisses everything a search found in one change (reverse.dismiss takes prefixes; --dismiss takes several).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,6 +6,98 @@ All notable changes to Jarl are documented here. The format follows
 
 ## [Unreleased]
 
+### Added
+
+- Reverse zones made easy (docs/reverse.md):
+  - **Missing reverse zones**: the Zones page and `jarl zone
+    suggest-reverse` list the reverse zones the private views lack for
+    their A and AAAA records' addresses: the /24 of a private IPv4 network,
+    a /32 for a public address (the rest of its /24 belongs to others),
+    the /48 of IPv6 addresses. Create one, or all (`--create`), filled.
+  - **Fill**: `jarl zone create 10.0.10.0/24 --fill` (ticked in the New
+    zone dialog) adds a PTR record for each address the view's records use
+    there; `jarl zone fill-ptr` and the reverse zone's page add the ones
+    missing later. An address with several names gets its mail or name
+    server's name, else a host's.
+  - **The right view**: a reverse zone created without a view goes to the
+    private view whose records use its addresses.
+  - **PTR records kept in step** per zone (`jarl zone update ZONE
+    --auto-ptr`, zone settings → Reverse DNS): adding, changing,
+    disabling or deleting an A or AAAA record does the same to its PTR
+    record, as the Update PTR box does for one change.
+  - Suggestions come in two groups: **yours** (private networks, a ULA or
+    an IPv6 /48 this server has an address in), which Create all
+    creates, and **public addresses**, each a /32 or /128 to create only
+    if it is yours (not a web host's) or **Dismiss**. A view can turn
+    suggestions off (`jarl view update vps --reverse-suggestions=false`),
+    e.g. one only a VPS uses.
+- A zone created inside another in the same view (a /24 inside a /8,
+  `lab.adbraun.lol` inside `adbraun.lol`) takes the parent's records
+  under it, which named would no longer serve from the parent; a
+  delegation and its glue stay.
+- Zone commands take a network for a reverse zone: `jarl zone show
+  10.0.10.0/24`.
+- **New reverse zone** (Zones page) lists the networks your records use
+  without a reverse zone, in every view, also where nothing is suggested
+  (suggestions off, dismissed, public views); pick one, change its size
+  (/48, /56, /64, /128 for IPv6, around the records' address) and create
+  it filled. With a view chosen, it also lists the addresses only other
+  views' records use, and fill names them from there (a VPS's AAAA in
+  external, its PTR in internal). `jarl zone suggest-reverse --all
+  [--view V]`. Both lists have a search, so hundreds of addresses stay
+  manageable: the public addresses fold away, show 25 at a time, and
+  **Dismiss these N** dismisses everything a search found in one change
+  (`--dismiss` takes several networks).
+- Comparing one name across views: `jarl zone diff adbraun.lol nas [A]`,
+  and a **Compare** button on each record.
+
+### Changed
+
+- **Compare views** and `jarl zone diff` are rebuilt around the view
+  you're on (docs/views.md#comparing-views): a summary per view, then
+  what is answered differently (a view's own records in linked zones,
+  drift otherwise) with **Use this everywhere**, the names only some
+  views have, grouped, with **Add to VIEW**, and how many are the same.
+  One line per record: the CLI cuts long TXT records to the terminal
+  (`--wide` shows them whole). `--with` picks the views to compare with.
+  `GET /zones/{zone}/compare` returns these sections instead of `rows`.
+
+### Fixed
+
+- Server options → Added by Jarl: long statements didn't wrap, and the
+  browser console reported a Content Security Policy violation (an inline
+  style the page's policy blocks).
+
+### Upgrading
+
+- The database gets two new versions (12 and 13), applied when jarld
+  starts; a 0.5 jarld can't open it afterwards, so take a backup first (`sudo
+  jarld backup`). Nothing changes until you turn `auto_ptr` on for a
+  zone.
+
+## [0.5.2] - 2026-10-12
+
+### Added
+
+- Mail reverse DNS check: the addresses of the public zones' MX hosts and
+  SPF records are looked up as the internet sees them, every 6 hours: a
+  PTR record whose name resolves back to the address, which Gmail and
+  Outlook require. It says who runs the reverse zone (your provider) and
+  what to set there, and notes when Jarl has its own reverse zone for the
+  address, which only your clients see. The Exposure page (Check now),
+  `jarl exposure mail` and Prometheus `jarl_mail_reverse_dns_ok`.
+- Added by Jarl: the Server options page, `jarl option generated` and
+  `GET /options/generated` list what Jarl writes into named.conf by
+  itself (keys.conf, the statistics channel and logging, blocking's
+  response-policy, the view keys), why, and what controls each.
+- `stats.rate_limit_log` (default true): `false` stops Jarl adding named's
+  `query-errors` category to its log channel when rate limiting is set.
+
+### Changed
+
+- Option values with a list of three or more elements (allow-query,
+  forwarders, listen-on, ...) are shown one element per line.
+
 ## [0.5.1] - 2026-10-12
 
 ### Added

README.md

@@ -25,7 +25,8 @@ error: www.adbraun.lol has a CNAME, so it can't have any other records (found A)
 ## Features
 
 * **Everything in one place**: primary, secondary, forward, stub, mirror,
-  hint, redirect and in-view zones, reverse zones from a CIDR, split DNS with
+  hint, redirect and in-view zones, reverse zones from a CIDR (suggested,
+  filled and kept in step from your A records), split DNS with
   views, ACLs, TSIG keys, and every BIND 9.20 option at server, view, zone
   and top level, with the ARM's description and grammar built in.
 * **Safe changes.** Every change is validated as a whole (CNAME rules,
@@ -147,6 +148,7 @@ in `/etc/jarl/jarl.yaml` to reach it from your management network.
 | [docs/encrypted-dns.md](docs/encrypted-dns.md) | DNS over TLS and HTTPS for your clients: setup, ports, client settings |
 | [docs/certificates.md](docs/certificates.md) | TLS certificates Jarl obtains and renews for its web UI and named's DNS over TLS/HTTPS |
 | [docs/stats.md](docs/stats.md) | Query statistics: enabling, what is collected, retention |
+| [docs/reverse.md](docs/reverse.md) | Reverse zones: suggested from your records, created in the right view and filled, PTR records kept in step |
 | [docs/exposure.md](docs/exposure.md) | Internet exposure: which views are public, hardening checks, response rate limiting |
 | [docs/metrics.md](docs/metrics.md) | Prometheus metrics: access, what is exported, example alerts |
 | [docs/blocking.md](docs/blocking.md) | Blocking ads, trackers and malware: blocklists, your own rules, views, memory |
@@ -200,7 +202,7 @@ review step.
 
 ## Status
 
-Version 0.5.1 is the current release. It adds Prometheus metrics,
+Version 0.5.2 is the current release. It adds Prometheus metrics,
 address ranges in ACLs and other address match lists, safer changeset
 handling, internet exposure checks with response rate limiting, TLS
 certificates Jarl obtains and renews itself, linked zones for split DNS,

VERSION

@@ -1 +1 @@
-0.5.1
+0.5.2

cmd/jarl/compare_test.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+	"unicode/utf8"
+)
+
+func TestPrintCompare(t *testing.T) {
+	long := `"v=spf1 ` + strings.Repeat("include:_spf.example.net ", 10) + `-all"`
+	r := &compareReport{Zone: "adbraun.lol", Base: "internal", Views: []string{"internal", "external"}, Linked: true}
+	r.Summary = append(r.Summary, struct {
+		View      string `json:"view"`
+		Different int    `json:"different"`
+		OnlyBase  int    `json:"only_base"`
+		OnlyOther int    `json:"only_other"`
+		Same      int    `json:"same"`
+	}{View: "external", Different: 1, OnlyBase: 1, Same: 5})
+	r.Different = []compareRow{{Name: "@", Type: "TXT", Views: []compareSet{
+		{View: "internal", Records: []string{long, `"short"`}, IDs: []int64{7, 8}, Linked: "local"},
+		{View: "external", Records: []string{`"other"`}, IDs: []int64{9}, Linked: "local"},
+	}}}
+	r.Only = append(r.Only, struct {
+		Views []string     `json:"views"`
+		Rows  []compareRow `json:"rows"`
+	}{Views: []string{"internal"}, Rows: []compareRow{{Name: "nas", Type: "A", Views: []compareSet{{View: "internal", Records: []string{"10.0.10.20"}}, {View: "external"}}}}})
+	r.Same = 5
+
+	var b bytes.Buffer
+	printCompare(&b, r, false, 60)
+	out := b.String()
+	// Record lines fit (the heading and summary are prose, and may wrap).
+	for _, l := range strings.Split(strings.TrimRight(out, "\n"), "\n")[3:] {
+		if n := utf8.RuneCountInString(l); n > 60 {
+			t.Errorf("line of %d characters: %q", n, l)
+		}
+	}
+	for _, want := range []string{
+		"adbraun.lol in internal, compared with external\n  linked: ",
+		"  external: 1 answered differently, 1 only in internal, 0 only in external, 5 the same",
+		"ANSWERED DIFFERENTLY (1)\n  @ TXT\n    internal  \"v=spf1 include:",
+		"…\n              \"short\"\n    external  \"other\"  [local, id 9]",
+		"ONLY IN INTERNAL (1)\n  nas A  10.0.10.20",
+		"5 names and types are the same (--all lists them)",
+	} {
+		if !strings.Contains(out, want) {
+			t.Errorf("output lacks %q:\n%s", want, out)
+		}
+	}
+	// Width 0: whole.
+	b.Reset()
+	printCompare(&b, r, false, 0)
+	if !strings.Contains(b.String(), long+"  [local, id 7]") {
+		t.Errorf("whole: %s", b.String())
+	}
+}

cmd/jarl/config_cmds.go

@@ -37,7 +37,7 @@ func viewCmd() *cobra.Command {
 	}
 	var clients, dests []string
 	var recursiveOnly, comment, exposure string
-	var adopt, cascade, yes bool
+	var adopt, cascade, yes, reverseSuggest bool
 	viewBody := func(cmd *cobra.Command) map[string]any {
 		body := map[string]any{}
 		f := cmd.Flags()
@@ -63,6 +63,9 @@ func viewCmd() *cobra.Command {
 		if f.Changed("exposure") {
 			body["exposure"] = exposure
 		}
+		if f.Changed("reverse-suggestions") {
+			body["reverse_suggestions"] = reverseSuggest
+		}
 		return body
 	}
 	addViewFlags := func(c *cobra.Command) {
@@ -71,6 +74,7 @@ func viewCmd() *cobra.Command {
 		c.Flags().StringVar(&recursiveOnly, "recursive-only", "", "match-recursive-only: yes, no or default")
 		c.Flags().StringVar(&comment, "comment", "", "comment")
 		c.Flags().StringVar(&exposure, "exposure", "", "reachable from the internet: auto (worked out), public or private (docs/exposure.md)")
+		c.Flags().BoolVar(&reverseSuggest, "reverse-suggestions", true, "suggest reverse zones for the view's addresses (--reverse-suggestions=false: don't; docs/reverse.md)")
 	}
 	create := &cobra.Command{
 		Use:   "create NAME",
@@ -721,7 +725,35 @@ func optionCmd() *cobra.Command {
 	}
 	scopeArgs(describe)
 	describe.Flags().StringVar(&zoneType, "zone-type", "primary", "with --zone: the zone type")
-	cmd.AddCommand(list, set, unset, describe)
+	generated := &cobra.Command{
+		Use:   "generated",
+		Short: "What Jarl adds to named.conf by itself, why, and what controls it",
+		Args:  cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			c, err := newClient()
+			if err != nil {
+				return err
+			}
+			var gen []struct {
+				Where   string `json:"where"`
+				Text    string `json:"text"`
+				Why     string `json:"why"`
+				Setting string `json:"setting"`
+			}
+			if err := c.Get(ctx(), "/options/generated", nil, &gen); err != nil {
+				return err
+			}
+			return output(gen, func(w io.Writer) {
+				for i, g := range gen {
+					if i > 0 {
+						fmt.Fprintln(w)
+					}
+					fmt.Fprintf(w, "# %s: %s\n# controlled by: %s\n%s\n", g.Where, g.Why, g.Setting, g.Text)
+				}
+			})
+		},
+	}
+	cmd.AddCommand(list, set, unset, describe, generated)
 	return cmd
 }
 

cmd/jarl/exposure.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"strings"
@@ -42,6 +43,54 @@ type exposureReport struct {
 			Count int64
 		} `json:"names"`
 	} `json:"rate_limiting"`
+	Mail *mailReport `json:"mail"`
+}
+
+type mailReport struct {
+	Checked string `json:"checked"`
+	Results []struct {
+		Zone      string   `json:"zone"`
+		Address   string   `json:"address"`
+		Roles     []string `json:"roles"`
+		PTR       []string `json:"ptr"`
+		OK        bool     `json:"ok"`
+		Level     string   `json:"level"`
+		Message   string   `json:"message"`
+		ManagedBy string   `json:"managed_by"`
+		LocalZone string   `json:"local_zone"`
+	} `json:"results"`
+	Errors []string `json:"errors"`
+}
+
+func printMail(w io.Writer, m *mailReport) {
+	if len(m.Results) == 0 && len(m.Errors) == 0 {
+		fmt.Fprintln(w, "No mail addresses: no public zone has an MX record or SPF addresses.")
+		return
+	}
+	fmt.Fprintln(w, "ZONE\tADDRESS\tFOR\tPTR\tSTATUS")
+	for _, r := range m.Results {
+		ptr := strings.Join(r.PTR, ",")
+		if ptr == "" {
+			ptr = "-"
+		}
+		fmt.Fprintf(w, "%s\t%s\t%s\t%s\t%s\n", r.Zone, r.Address, strings.Join(r.Roles, ", "), ptr, r.Level)
+		if r.Level != "ok" {
+			fmt.Fprintf(w, "  %s\n", r.Message)
+		}
+		if r.LocalZone != "" {
+			fmt.Fprintf(w, "  Jarl's reverse zone %s only answers inside: receivers ask %s\n", r.LocalZone, orOwner(r.ManagedBy))
+		}
+	}
+	for _, e := range m.Errors {
+		fmt.Fprintf(w, "error: %s\n", e)
+	}
+}
+
+func orOwner(s string) string {
+	if s == "" {
+		return "the address's owner"
+	}
+	return s
 }
 
 // exposureScope turns "server" (or "") into the server, anything else
@@ -115,6 +164,10 @@ fix Jarl can stage for each.`,
 						}
 					}
 				}
+				if r.Mail != nil {
+					fmt.Fprintln(w, "\nMAIL REVERSE DNS")
+					printMail(w, r.Mail)
+				}
 				if a := r.RateLimiting; a != nil && len(a.Counts) > 0 {
 					fmt.Fprintf(w, "\nRATE LIMITING, LAST %s\n", a.Since)
 					for _, e := range a.Counts {
@@ -186,6 +239,33 @@ fix Jarl can stage for each.`,
 			return report(resp)
 		},
 	}
-	cmd.AddCommand(fix, ack, unack)
+	mail := &cobra.Command{
+		Use:   "mail",
+		Short: "Check the reverse DNS of the addresses that send and receive your mail, now",
+		Long: `Finds the addresses of the public zones' MX hosts and SPF records and checks,
+through public resolvers, that each has a PTR record whose name resolves
+back to it, as Gmail and Outlook do. Exits 1 when one doesn't.`,
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			c, err := newClient()
+			if err != nil {
+				return err
+			}
+			var m mailReport
+			if err := c.Do(ctx(), "POST", "/exposure/mail", nil, map[string]any{}, &m); err != nil {
+				return err
+			}
+			if err := output(m, func(w io.Writer) { printMail(w, &m) }); err != nil {
+				return err
+			}
+			for _, r := range m.Results {
+				if !r.OK {
+					return errors.New("some mail addresses have no working reverse DNS")
+				}
+			}
+			return nil
+		},
+	}
+	cmd.AddCommand(fix, ack, unack, mail)
 	return cmd
 }

cmd/jarl/main.go

@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net/netip"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -23,6 +24,7 @@ import (
 
 	"jarl/internal/api"
 	"jarl/internal/client"
+	"jarl/internal/dnsname"
 	"jarl/internal/version"
 )
 
@@ -569,7 +571,13 @@ func q(kv ...string) url.Values {
 }
 
 // zonePath returns the API path for a zone given by name or ID.
+// A network names its reverse zone: 10.0.10.0/24 is 10.0.10.in-addr.arpa.
 func zonePath(zone, view string) (string, url.Values) {
+	if p, err := netip.ParsePrefix(strings.TrimSpace(zone)); err == nil {
+		if name, err := dnsname.ReverseZone(p); err == nil {
+			zone = name
+		}
+	}
 	z := strings.TrimSuffix(zone, ".")
 	if zone == "." {
 		z = "root"

cmd/jarl/zones.go

@@ -93,6 +93,15 @@ func zoneCmd() *cobra.Command {
 				if z.InView != "" {
 					fmt.Fprintf(w, "In view:\t%s\n", z.InView)
 				}
+				if z.AutoPTR {
+					fmt.Fprintf(w, "PTR records:\tkept in step with the A and AAAA records\n")
+				}
+				if z.Prefix != "" {
+					fmt.Fprintf(w, "Network:\t%s\n", z.Prefix)
+					if z.PTRMissing > 0 {
+						fmt.Fprintf(w, "Missing PTRs:\t%d (addresses the view's records use here; add them: jarl zone fill-ptr %s)\n", z.PTRMissing, args[0])
+					}
+				}
 				if len(z.LinkedWith) > 0 {
 					fmt.Fprintf(w, "Linked with:\t%s (shared records are kept in step; 'jarl record list' shows which are local)\n", strings.Join(z.LinkedWith, ", "))
 				}
@@ -110,17 +119,21 @@ func zoneCmd() *cobra.Command {
 	var ns, records, primaries, forwarders, opts []string
 	var contact, comment, cloneFrom, file, inView, forward, linkWith string
 	var ttl uint32
+	var fill bool
 	create := &cobra.Command{
 		Use:   "create NAME",
 		Short: "Create a zone",
 		Long: `Create a zone. NAME may be a network (192.168.1.0/24, 2001:db8::/48) to
 create its reverse zone: a /32 (or /128) gives a zone for that one address,
 and a network between octet boundaries, like a /22, gets one zone per /24
-(created together).
+(created together). Without --view, a reverse zone goes to the private
+view whose records use its addresses; --fill adds a PTR record for each
+of them (docs/reverse.md).
 
   jarl zone create example.com --ns ns1.example.com. --record "ns1 A 192.0.2.1"
   jarl zone create 192.168.1.0/24
   jarl zone create 10.0.8.0/22            # 8-11.0.10.in-addr.arpa
+  jarl zone create 10.0.10.0/24 --fill    # with PTR records for the view's A records there
   jarl zone create partner.example --type secondary --primary 192.0.2.53
   jarl zone create consul --type forward --forwarder "127.0.0.1 port 8600"
   jarl zone create example.com --view external --clone-from example.com --clone-view internal
@@ -156,6 +169,9 @@ and a network between octet boundaries, like a /22, gets one zone per /24
 			if linkWith != "" {
 				body["link_with"] = linkWith
 			}
+			if fill {
+				body["fill"] = true
+			}
 			var recs []map[string]any
 			for _, r := range records {
 				f := strings.Fields(r)
@@ -228,9 +244,11 @@ and a network between octet boundaries, like a /22, gets one zone per /24
 	create.Flags().StringVar(&inView, "in-view", "", "for in-view zones: the view to share the zone from")
 	create.Flags().StringVar(&linkWith, "link-with", "", "link with the zone of the same name in this view: copy its shared records and keep them in step (docs/views.md#linked-zones)")
 	create.Flags().StringVar(&comment, "comment", "", "comment")
+	create.Flags().BoolVar(&fill, "fill", false, "reverse zones: add PTR records for the view's A and AAAA records in the network")
 
 	var refresh, retry, expire, minimum, serial uint32
 	var mname, policy, moveView string
+	var autoPTR bool
 	update := &cobra.Command{
 		Use:   "update ZONE",
 		Short: "Change a zone's settings (SOA, TTL, view, comment)",
@@ -272,6 +290,9 @@ and a network between octet boundaries, like a /22, gets one zone per /24
 			if f.Changed("file") {
 				body["file"] = file
 			}
+			if f.Changed("auto-ptr") {
+				body["auto_ptr"] = autoPTR
+			}
 			if len(body) == 0 {
 				return fmt.Errorf("nothing to change (see --help)")
 			}
@@ -296,6 +317,7 @@ and a network between octet boundaries, like a /22, gets one zone per /24
 	update.Flags().StringVar(&comment, "comment", "", "comment")
 	update.Flags().StringVar(&moveView, "move-to-view", "", "move the zone to this view")
 	update.Flags().StringVar(&file, "file", "", "zone file (secondary, hint and redirect zones)")
+	update.Flags().BoolVar(&autoPTR, "auto-ptr", false, "keep the PTR records of the zone's A and AAAA records in step (--auto-ptr=false: stop)")
 
 	var yes bool
 	del := &cobra.Command{
@@ -424,7 +446,7 @@ equal to the file: records not in the file are deleted.`,
 	importCmd.Flags().BoolVar(&replace, "replace", false, "delete records that are not in the file")
 	importCmd.Flags().BoolVar(&useSOA, "use-soa", false, "also take SOA timers and $TTL from the file")
 
-	cmd.AddCommand(list, show, create, update, del, toggle(true), toggle(false), fileCmd, importCmd, zoneSerialsCmd(), zoneDelegationCmd(), zoneDNSSECCmd(), zoneRegistrarCmd(), zoneLinkCmd(true), zoneLinkCmd(false), zoneDiffCmd())
+	cmd.AddCommand(list, show, create, update, del, toggle(true), toggle(false), fileCmd, importCmd, zoneSerialsCmd(), zoneDelegationCmd(), zoneDNSSECCmd(), zoneRegistrarCmd(), zoneLinkCmd(true), zoneLinkCmd(false), zoneDiffCmd(), zoneFillPTRCmd(), zoneSuggestReverseCmd())
 	return cmd
 }
 
@@ -940,87 +962,363 @@ zone is dissolved.`
 
 // zoneDiffCmd is 'zone diff': a zone's records side by side in the views
 // that have it.
+type compareSet struct {
+	View    string   `json:"view"`
+	Records []string `json:"records"`
+	IDs     []int64  `json:"ids"`
+	Linked  string   `json:"linked"`
+}
+
+type compareRow struct {
+	Name  string       `json:"name"`
+	Type  string       `json:"type"`
+	Views []compareSet `json:"views"`
+}
+
+type compareReport struct {
+	Zone    string   `json:"zone"`
+	Base    string   `json:"base"`
+	Views   []string `json:"views"`
+	Linked  bool     `json:"linked"`
+	Summary []struct {
+		View      string `json:"view"`
+		Different int    `json:"different"`
+		OnlyBase  int    `json:"only_base"`
+		OnlyOther int    `json:"only_other"`
+		Same      int    `json:"same"`
+	} `json:"summary"`
+	Different []compareRow `json:"different"`
+	Only      []struct {
+		Views []string     `json:"views"`
+		Rows  []compareRow `json:"rows"`
+	} `json:"only"`
+	Same     int          `json:"same"`
+	SameRows []compareRow `json:"same_rows"`
+}
+
 func zoneDiffCmd() *cobra.Command {
-	var views []string
-	var all bool
+	var view string
+	var with []string
+	var all, wide bool
 	cmd := &cobra.Command{
-		Use:   "diff ZONE [--view V --view W] [--all]",
-		Short: "Show what differs between the views that have a zone",
-		Long: `Lines up a zone's records in the views that have it (or the views
-given), one row per name and type, and shows the ones that differ: a
-local override in a linked zone, a record one view lacks. With --all, the
-ones that are the same too. In a linked zone, 'jarl record update ID
---shared' makes a view's version every view's.`,
+		Use:   "diff ZONE [NAME [TYPE]] [--view V] [--with W...] [--all] [--wide]",
+		Short: "Compare a zone with the same zone in other views",
+		Long: `Compares a zone in one view (--view, default the first view that has it)
+with the same zone in the other views (--with, default all of them): how
+many names each answers differently, the names and types only some views
+have, and how many are the same. NAME (and TYPE) narrows it to one name,
+the same records included. One line per record; long values are cut to
+fit the terminal (--wide shows them whole).
+
+In a linked zone a difference is a view's own (local) records, on
+purpose; between zones that aren't linked it is drift. 'jarl record
+update ID --shared' makes a linked view's version every view's.`,
 		Example: `  jarl zone diff adbraun.lol
-  jarl zone diff adbraun.lol --view internal --view external --all`,
+  jarl zone diff adbraun.lol --view internal --with external
+  jarl zone diff adbraun.lol nas
+  jarl zone diff adbraun.lol @ TXT --wide`,
+		Args: cobra.RangeArgs(1, 3),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			c, err := newClient()
+			if err != nil {
+				return err
+			}
+			path, qv := zonePath(args[0], view)
+			if len(with) > 0 {
+				qv.Set("with", strings.Join(with, ","))
+			}
+			if len(args) > 1 {
+				qv.Set("name", args[1])
+			}
+			if len(args) > 2 {
+				qv.Set("type", args[2])
+			}
+			if all {
+				qv.Set("all", "1")
+			}
+			var r compareReport
+			if err := c.Get(ctx(), path+"/compare", qv, &r); err != nil {
+				return err
+			}
+			width := 0
+			if !wide {
+				width = terminalWidth()
+			}
+			return output(r, func(w io.Writer) { printCompare(w, &r, len(args) > 1, width) })
+		},
+	}
+	cmd.Flags().StringVar(&view, "view", "", "the view to compare from (default: the first that has the zone)")
+	cmd.Flags().StringArrayVar(&with, "with", nil, "a view to compare with (repeat; default: every other view with the zone)")
+	cmd.Flags().BoolVar(&all, "all", false, "also list what is the same")
+	cmd.Flags().BoolVarP(&wide, "wide", "w", false, "show long values whole instead of cutting them to the terminal")
+	return cmd
+}
+
+// printCompare prints a comparison as sections, one line per record,
+// each cut to width characters (0: whole).
+func printCompare(w io.Writer, r *compareReport, oneName bool, width int) {
+	vw := 0 // the views column
+	for _, v := range r.Views {
+		vw = max(vw, len(v))
+	}
+	line := func(indent, label, text string) {
+		s := indent + label + text
+		if width > 0 && utf8.RuneCountInString(s) > width {
+			keep := max(width-utf8.RuneCountInString(indent+label)-1, 8)
+			text = string([]rune(text)[:min(keep, utf8.RuneCountInString(text))]) + "…"
+		}
+		fmt.Fprintln(w, indent+label+text)
+	}
+	link := "not linked, so a difference may have crept in ('jarl zone link " + r.Zone + "' keeps them in step)"
+	if r.Linked {
+		link = "linked: a difference is a view's own records, there on purpose"
+	}
+	fmt.Fprintf(w, "%s in %s, compared with %s\n  %s\n", r.Zone, r.Base, strings.Join(r.Views[1:], ", "), link)
+	if !oneName {
+		for _, s := range r.Summary {
+			fmt.Fprintf(w, "  %s: %d answered differently, %d only in %s, %d only in %s, %d the same\n", s.View, s.Different, s.OnlyBase, r.Base, s.OnlyOther, s.View, s.Same)
+		}
+	}
+	name := func(row compareRow) string { return row.Name + " " + row.Type }
+	sets := func(row compareRow, local bool) {
+		for _, vs := range row.Views {
+			label := fmt.Sprintf("    %-*s  ", vw, vs.View)
+			if len(vs.Records) == 0 {
+				line("", label, "-")
+				continue
+			}
+			for i, d := range vs.Records {
+				if i > 0 {
+					label = strings.Repeat(" ", 4+vw+2)
+				}
+				suffix := ""
+				if local && vs.Linked == "local" && i == 0 {
+					suffix = "  [local, id " + fmt.Sprint(vs.IDs[0]) + "]"
+				}
+				line("", label, d+suffix)
+			}
+		}
+	}
+	if len(r.Different) > 0 {
+		fmt.Fprintf(w, "\nANSWERED DIFFERENTLY (%d)\n", len(r.Different))
+		for _, row := range r.Different {
+			fmt.Fprintln(w, "  "+name(row))
+			sets(row, true)
+		}
+	}
+	for _, o := range r.Only {
+		fmt.Fprintf(w, "\nONLY IN %s (%d)\n", strings.ToUpper(strings.Join(o.Views, ", ")), len(o.Rows))
+		nw := 0
+		for _, row := range o.Rows {
+			nw = max(nw, len(name(row)))
+		}
+		for _, row := range o.Rows {
+			var recs []string
+			for _, vs := range row.Views {
+				if len(vs.Records) > 0 {
+					recs = vs.Records
+					break
+				}
+			}
+			for i, d := range recs {
+				label := fmt.Sprintf("  %-*s  ", nw, name(row))
+				if i > 0 {
+					label = strings.Repeat(" ", 2+nw+2)
+				}
+				line("", label, d)
+			}
+		}
+	}
+	if len(r.SameRows) > 0 {
+		fmt.Fprintf(w, "\nTHE SAME IN %s (%d)\n", strings.ToUpper(strings.Join(r.Views, ", ")), len(r.SameRows))
+		nw := 0
+		for _, row := range r.SameRows {
+			nw = max(nw, len(name(row)))
+		}
+		for _, row := range r.SameRows {
+			for i, d := range row.Views[0].Records {
+				label := fmt.Sprintf("  %-*s  ", nw, name(row))
+				if i > 0 {
+					label = strings.Repeat(" ", 2+nw+2)
+				}
+				line("", label, d)
+			}
+		}
+	} else if r.Same > 0 && !oneName {
+		fmt.Fprintf(w, "\n%d names and types are the same (--all lists them)\n", r.Same)
+	}
+	if oneName && len(r.Different) == 0 && len(r.Only) == 0 && len(r.SameRows) == 0 {
+		fmt.Fprintln(w, "\nNo records of that name in these views.")
+	}
+}
+
+// terminalWidth returns the terminal's width, or 0 when standard output
+// isn't a terminal (then nothing is cut).
+func terminalWidth() int {
+	fd := int(os.Stdout.Fd())
+	if !term.IsTerminal(fd) {
+		return 0
+	}
+	width, _, err := term.GetSize(fd)
+	if err != nil || width <= 0 {
+		return 0
+	}
+	return width
+}
+
+func zoneFillPTRCmd() *cobra.Command {
+	var view string
+	cmd := &cobra.Command{
+		Use:   "fill-ptr ZONE [--view VIEW]",
+		Short: "Add the PTR records a reverse zone lacks for its view's A and AAAA records",
+		Long: `Adds a PTR record to a reverse zone for every address in its network that
+the view's A and AAAA records use and that has none yet. An address with
+several names gets the mail or name server's name, else a host's rather
+than the domain's, else the shortest (docs/reverse.md).`,
+		Example: `  jarl zone fill-ptr 10.0.10.0/24
+  jarl zone fill-ptr 10.0.10.in-addr.arpa --view internal`,
 		Args: cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			c, err := newClient()
 			if err != nil {
 				return err
 			}
-			path, qv := zonePath(args[0], "")
-			if len(views) > 0 {
-				qv.Set("views", strings.Join(views, ","))
-			}
-			if all {
-				qv.Set("all", "1")
-			}
-			var r struct {
-				Zone   string   `json:"zone"`
-				Views  []string `json:"views"`
-				Linked bool     `json:"linked"`
-				Same   int      `json:"same"`
-				Rows   []struct {
-					Name  string `json:"name"`
-					Type  string `json:"type"`
-					Same  bool   `json:"same"`
-					Views []struct {
-						Records []string `json:"records"`
-						IDs     []int64  `json:"ids"`
-						Linked  string   `json:"linked"`
-					} `json:"views"`
-				} `json:"rows"`
-			}
-			if err := c.Get(ctx(), path+"/compare", qv, &r); err != nil {
+			path, qv := zonePath(args[0], view)
+			resp, err := c.Mutate(ctx(), "POST", path+"/fill-ptr", qv, nil)
+			if err != nil {
 				return err
 			}
-			return output(r, func(w io.Writer) {
-				head := []string{"NAME", "TYPE"}
-				for _, v := range r.Views {
-					head = append(head, strings.ToUpper(v))
-				}
-				fmt.Fprintln(w, strings.Join(head, "\t"))
-				for _, row := range r.Rows {
-					cols := []string{row.Name, row.Type}
-					for _, vs := range row.Views {
-						cell := "-"
-						if len(vs.Records) > 0 {
-							cell = strings.Join(vs.Records, ", ")
-							if vs.Linked == "local" {
-								cell += " [local, id " + fmt.Sprint(vs.IDs[0]) + "]"
-							}
-						}
-						cols = append(cols, cell)
-					}
-					fmt.Fprintln(w, strings.Join(cols, "\t"))
-				}
-				link := "not linked (jarl zone link " + r.Zone + ")"
-				if r.Linked {
-					link = "linked"
-				}
-				fmt.Fprintf(w, "\n%d names and types differ, %d are the same; %s\n", len(r.Rows)-boolCount(all, r.Same), r.Same, link)
-			})
+			return report(resp)
 		},
 	}
-	cmd.Flags().StringArrayVar(&views, "view", nil, "a view to compare (repeat; default: every view with the zone)")
-	cmd.Flags().BoolVar(&all, "all", false, "also show what is the same everywhere")
+	cmd.Flags().StringVar(&view, "view", "", "view of the zone")
 	return cmd
 }
 
-func boolCount(b bool, n int) int {
-	if b {
-		return n
-	}
-	return 0
+type reverseSuggestion struct {
+	ViewID  int64    `json:"view_id"`
+	View    string   `json:"view"`
+	Prefix  string   `json:"prefix"`
+	Zone    string   `json:"zone"`
+	Group   string   `json:"group"`
+	Hidden  string   `json:"hidden"`
+	Why     string   `json:"why"`
+	Fill    int      `json:"fill"`
+	Samples []string `json:"samples"`
+}
+
+func zoneSuggestReverseCmd() *cobra.Command {
+	var create, all bool
+	var dismiss, undismiss []string
+	var view string
+	cmd := &cobra.Command{
+		Use:   "suggest-reverse [--create] [--dismiss NETWORK --view V]",
+		Short: "The reverse zones your private views lack for their records' addresses",
+		Long: `Lists the reverse zones the private views (or the server, without views)
+lack for the addresses of their A and AAAA records, in two groups:
+
+  yours    the /24 of a private IPv4 network, the /48 of a ULA or of an IPv6
+           prefix this server has an address in
+  public   a /32 (or /128) for any other public address: create it only if
+           the address is yours, not a web host's
+
+--create creates the ones that are yours, filled with PTR records, in one
+changeset; create a public one with 'jarl zone create NETWORK --view V
+--fill'. --dismiss hides a suggestion for good (--undismiss shows it
+again). A view can stop suggestions: jarl view update V
+--reverse-suggestions=false (docs/reverse.md).
+
+--all lists every network the views' records use without a reverse zone,
+also where nothing is suggested unasked (a view with suggestions off, a
+dismissed network, a public view), to create one by hand; --view narrows
+the list to one view. Change the size as you need: a /48 suggested for
+IPv6 can be created as a /56 or /64 instead.`,
+		Example: `  jarl zone suggest-reverse
+  jarl zone suggest-reverse --create
+  jarl zone create 139.144.144.154/32 --view internal --fill
+  jarl zone suggest-reverse --dismiss 185.199.108.153/32 --view internal
+  jarl zone suggest-reverse --all --view vps
+  jarl zone create 2a02:8013:7f3d::/48 --view internal --fill`,
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			c, err := newClient()
+			if err != nil {
+				return err
+			}
+			if len(dismiss) > 0 || len(undismiss) > 0 {
+				path, prefixes := "/reverse-zones/dismiss", dismiss
+				if len(undismiss) > 0 {
+					path, prefixes = "/reverse-zones/undismiss", undismiss
+				}
+				resp, err := c.Mutate(ctx(), "POST", path, nil, map[string]any{"view": view, "prefixes": prefixes})
+				if err != nil {
+					return err
+				}
+				return report(resp)
+			}
+			if create && (all || view != "") {
+				return fmt.Errorf("--create creates the suggestions that are yours; create others one by one: jarl zone create NETWORK --view VIEW --fill")
+			}
+			qv := q("view", view)
+			if all {
+				qv.Set("all", "1")
+			}
+			var sugg []reverseSuggestion
+			if err := c.Get(ctx(), "/reverse-zones/suggestions", qv, &sugg); err != nil {
+				return err
+			}
+			if !create {
+				return output(sugg, func(w io.Writer) {
+					if len(sugg) == 0 {
+						fmt.Fprintln(w, "No reverse zones missing.")
+						return
+					}
+					head := "GROUP\tVIEW\tNETWORK\tZONE\tPTRS\tFOR EXAMPLE"
+					if all {
+						head = "GROUP\tVIEW\tNETWORK\tZONE\tPTRS\tHIDDEN\tFOR EXAMPLE"
+					}
+					fmt.Fprintln(w, head)
+					for _, s := range sugg {
+						v := s.View
+						if v == "" {
+							v = "-"
+						}
+						cols := []string{s.Group, v, s.Prefix, s.Zone, fmt.Sprint(s.Fill)}
+						if all {
+							cols = append(cols, orDash(s.Hidden))
+						}
+						cols = append(cols, strings.Join(s.Samples, ", "))
+						fmt.Fprintln(w, strings.Join(cols, "\t"))
+					}
+					fmt.Fprintln(w, "\nCreate yours, filled: jarl zone suggest-reverse --create. A public one only if the address is yours:\njarl zone create NETWORK --view VIEW --fill (or hide it: --dismiss NETWORK --view VIEW).")
+				})
+			}
+			var reqs []api.ChangeRequest
+			for _, s := range sugg {
+				if s.Group != "yours" {
+					continue
+				}
+				body := map[string]any{"name": s.Prefix, "fill": true}
+				if s.ViewID != 0 {
+					body["view_id"] = s.ViewID
+				}
+				data, err := json.Marshal(body)
+				if err != nil {
+					return err
+				}
+				reqs = append(reqs, api.ChangeRequest{Op: "zone.create", Data: data})
+			}
+			if len(reqs) == 0 {
+				fmt.Println("No reverse zones of yours missing (public addresses are created one by one: see 'jarl zone suggest-reverse').")
+				return nil
+			}
+			return submitBatch(c, fmt.Sprintf("%d suggested reverse zones", len(reqs)), reqs)
+		},
+	}
+	cmd.Flags().BoolVar(&create, "create", false, "create the ones that are yours, filled with PTR records")
+	cmd.Flags().StringSliceVar(&dismiss, "dismiss", nil, "hide the suggestions for these networks (comma separated or repeated)")
+	cmd.Flags().StringSliceVar(&undismiss, "undismiss", nil, "show dismissed suggestions again")
+	cmd.Flags().StringVar(&view, "view", "", "only this view; with --dismiss/--undismiss: the suggestion's view")
+	cmd.Flags().BoolVar(&all, "all", false, "also networks not suggested unasked (suggestions off, dismissed, public views)")
+	return cmd
 }

cmd/jarld/main.go

@@ -188,6 +188,7 @@ func renderExtras(cfg *config.Config) render.Extras {
 		h := &render.StatsHooks{Channel: netip.MustParseAddrPort(cfg.Stats.StatisticsChannel)}
 		if cfg.Stats.QueryLog {
 			h.LogFile, h.LogVersions, h.LogSize = cfg.Stats.LogFile, cfg.Stats.LogVersions, cfg.Stats.LogSize
+			h.NoRateLimitLog = !cfg.Stats.RateLimitLog
 		}
 		x.Stats = h
 	}
@@ -333,7 +334,9 @@ func serveCmd() *cobra.Command {
 				TOTPRequire: a.cfg.TOTP.Require, TOTPIssuer: a.cfg.TOTP.IssuerName(),
 				Metrics: server.Metrics{Enabled: a.cfg.Metrics.Enabled, Listen: a.cfg.Metrics.Listen,
 					Allow: a.cfg.Metrics.AllowPrefixes(), Token: a.cfg.Metrics.Token},
-				Certs: cm,
+				Certs:        cm,
+				Resolvers:    a.cfg.ACME.Resolvers,
+				RateLimitLog: a.cfg.Stats.Enabled && a.cfg.Stats.QueryLog && a.cfg.Stats.RateLimitLog,
 				HTTPReq: server.HTTPReq{
 					Enabled:           a.cfg.ACME.HTTPReq.Enabled,
 					AllowPlainHTTP:    !a.cfg.ACME.HTTPReq.RequireHTTPS,

docs/api.md

@@ -190,6 +190,7 @@ ZoneInput:
 ```json
 {
   "name": "adbraun.lol",              // or a CIDR like "192.168.1.0/24" for a reverse zone
+  "fill": true,                       // reverse zones: PTR records for the view's A/AAAA records there
   "view": "internal",                 // or "view_id"; moving a zone = PATCH with another view
   "type": "primary",                  // secondary, stub, static-stub, forward, mirror, hint, redirect, in-view
   "in_view": "internal",              // type in-view only
@@ -199,6 +200,7 @@ ZoneInput:
   "default_ttl": 3600,
   "serial_policy": "date",            // date, increment, unixtime
   "dnssec_policy": "default",         // primary zones: "" (off), "default", a custom policy, "insecure" (turning off)
+  "auto_ptr": true,                   // keep the PTRs of the zone's A/AAAA records in step (docs/reverse.md)
   "comment": "",
   // create only:
   "nameservers": ["ns1.adbraun.lol."],                     // default: settings
@@ -208,6 +210,11 @@ ZoneInput:
 }
 ```
 
+A reverse zone created without a view goes to the private view whose
+records use its addresses. Zones come back with `prefix` (reverse zones:
+the network) and `ptr_missing` (addresses in it that the view's A and AAAA
+records use, without a PTR record).
+
 `/serials` and `/delegation` send DNS queries from the server, and only
 when called ([operations.md](operations.md#checking-name-servers-and-the-delegation)).
 `/serials` works for primary, secondary and mirror zones:
@@ -353,7 +360,10 @@ and `linked_with` (the other views).
 |--------|------|------|
 | POST | `/zones/{zone}/link` | `{"with": ["external"]}` (default: every view with that zone). Names and types that are the same everywhere become shared, the rest stay local |
 | POST | `/zones/{zone}/unlink` | Takes the zone out of its link; its records stay, all local |
-| GET | `/zones/{zone}/compare` | The zone across the views that have it (`?views=a,b`; `?all=1` also the same rows): `views`, `linked`, `same` (count) and `rows` (name, type, `same`, per view `records`, `ids`, `linked`). The zone may be named without a view |
+| POST | `/zones/{zone}/fill-ptr` | Adds the PTR records a reverse zone lacks for its view's A and AAAA records ([reverse.md](reverse.md)) |
+| GET | `/reverse-zones/suggestions` | The reverse zones the private views lack (`?all=1`: also the ones not suggested unasked, with `hidden`: public view, suggestions off, dismissed; `?view=`: one view): `view_id`, `view`, `prefix`, `zone`, `group` (`yours`, or `public`: only if the address is yours), `why`, `fill` (PTR records it would get), `samples` |
+| POST | `/reverse-zones/dismiss` | `{"view": "internal", "prefix": "185.199.108.153/32"}` (or `"prefixes": [...]` for several): don't suggest it again (`/undismiss` brings it back). A view's `reverse_suggestions: false` (PATCH `/views/{id}`) stops its suggestions |
+| GET | `/zones/{zone}/compare` | The zone compared with the same zone in other views, from its own view ([views.md](views.md#comparing-views)): `?with=a,b` (default: all), `?name=www&type=A` (one name, the same records included), `?all=1`. Returns `base`, `views`, `linked`, `summary` (per other view: `different`, `only_base`, `only_other`, `same`), `different` and `only` (`views`, `rows`) rows (name, `fqdn`, type, per view `records`, `data`, `ids`, `ttl`, `linked`), `same`, `same_rows`. A zone named without its view is compared from the first view that has it |
 
 `POST /zones` takes `"link_with": "VIEW"` to create a zone linked with
 that view's zone of the same name.
@@ -470,7 +480,8 @@ listing with `?changeset=` marks them `pending`.
 
 | Method | Path | Body / query |
 |--------|------|--------------|
-| GET | `/options` | `?scope=options\|view\|zone\|toplevel&scope_id=ID` (none: everything you may see) |
+| GET | `/options` | `?scope=options\|view\|zone\|toplevel&scope_id=ID` (none: everything you may see). `formatted` lays out a block over several lines, a list of three or more one element per line |
+| GET | `/options/generated` | What Jarl adds to named.conf by itself: `where`, `text`, `why`, `setting` (what turns it on or off) |
 | POST | `/options` | `{"scope": "zone", "scope_id": 11, "name": "allow-transfer", "value": "{ key xfer; }", "comment": "", "position": 0}` |
 | GET / PATCH / DELETE | `/options/{id}` | |
 | GET / PATCH | `/settings` | `{"nameservers": [...], "rname": "...", "default_ttl": 3600, "refresh": ..., "retry": ..., "expire": ..., "negative_ttl": ..., "serial_policy": "date"}` |

docs/cli.md

@@ -177,6 +177,13 @@ jarl zone create lab.adbraun.lol --ns ns1.adbraun.lol.
 jarl zone create 192.168.20.0/24                       # reverse zone from a network
 jarl zone create 10.0.8.0/22                           # four zones, 8-11.0.10.in-addr.arpa
 jarl zone create 10.0.10.100/32                        # a zone for just that address
+jarl zone create 10.0.10.0/24 --fill                   # in the view whose records use it, with their PTRs
+jarl zone fill-ptr 10.0.10.0/24                        # add the PTRs it lacks (zone commands take a network too)
+jarl zone suggest-reverse [--create]                   # reverse zones your private views lack (--create: yours)
+jarl zone suggest-reverse --dismiss 185.199.108.153/32,185.199.109.153/32 --view internal   # not yours: don't suggest them again
+jarl zone suggest-reverse --all [--view V]             # every network without a reverse zone, also the hidden ones
+jarl view update vps --reverse-suggestions=false       # no suggestions for this view
+jarl zone update adbraun.lol --auto-ptr                # keep PTRs in step with the A/AAAA records (docs/reverse.md)
 jarl zone create adbraun.lol --view external --clone-from adbraun.lol --clone-view internal
 jarl zone create partner.example --type secondary --primary "192.0.2.53 key xfer"
 jarl zone create consul --type forward --forwarder "127.0.0.1 port 8600"
@@ -221,7 +228,8 @@ jarl zone unlink adbraun.lol --view vps
 jarl record add adbraun.lol nas A 10.0.10.20 --view internal --local   # this view only
 jarl record set adbraun.lol www A 10.0.10.5 --view internal --local    # override the shared www A here
 jarl record update 1234 --local | --shared
-jarl zone diff adbraun.lol [--view V --view W] [--all]                 # what differs between the views
+jarl zone diff adbraun.lol [--view V] [--with W] [--all] [--wide]   # compared with the same zone in other views
+jarl zone diff adbraun.lol nas [A]                                     # just one name
 ```
 
 When a zone exists in several views, add `--view NAME` to commands that
@@ -405,6 +413,7 @@ jarl exposure                                         # public views, findings,
 jarl exposure fix external exposure_rate_limit        # rate limiting, log-only first
 jarl exposure fix external exposure_rate_limit_log_only   # then start enforcing
 jarl exposure fix server exposure_version
+jarl exposure mail                                   # reverse DNS of the addresses that send and receive mail
 jarl exposure ack external security_open_resolver --reason "public resolver, monitored"
 jarl exposure unack external security_open_resolver
 jarl view update external --exposure public|private|auto
@@ -476,6 +485,7 @@ jarl option set logging '{ channel q { file "/var/log/named/query.log" versions
 jarl option unset forwarders
 jarl option describe                          # every option allowed at this scope
 jarl option describe allow-query-cache        # grammar and ARM description
+jarl option generated                         # what Jarl adds to named.conf by itself, and why
 ```
 
 Options that end in a list (`allow-*`, `forwarders`, `listen-on`, ...) may

docs/concepts.md

@@ -48,6 +48,14 @@ overwritten. Jarl records a checksum of every file it writes and reports
 **drift** when a file changes behind its back. It then refuses to overwrite
 the file until you say so (`--force`, or `jarl resync --force`).
 
+Some of named.conf comes from Jarl itself rather than from your options:
+the include of keys.conf, the statistics channel and the logging
+statistics need, blocking's `response-policy` and policy zones, and the
+view keys at the front of each view's `match-clients`. The Server options
+page lists them under **Added by Jarl**, with why each is there and what
+turns it on or off (`jarl option generated`). Where you have a statement
+of your own (`logging`, `statistics-channels`), Jarl merges into it.
+
 Comments are part of the data model: zones, records, ACLs, views, keys and
 options can all carry a comment, and Jarl writes it into the generated file.
 Comments in imported zone files are kept.
@@ -250,6 +258,11 @@ boundary. So:
   (RFC 2317 delegation, where an ISP hands you part of a /24, is set up by
   hand with CNAMEs.)
 
+Jarl suggests the reverse zones your private views lack, creates them in
+the right view filled with PTR records, and can keep PTR records in step
+with a zone's A and AAAA records: [reverse.md](reverse.md). A zone created
+inside another (a /24 inside a /8) takes the parent's records under it.
+
 ### Dynamic updates and TSIG keys
 
 Jarl writes every zone file, so it can't let named change a zone through

docs/exposure.md

@@ -107,7 +107,10 @@ is only in its log (category `query-errors`). That is why the activity
 needs query statistics; without them, look at named's log for
 `would rate limit`. When rate limiting is configured and statistics are
 on, Jarl adds `query-errors` to its log channel (keeping named's syslog
-destination for it).
+destination for it). `stats.rate_limit_log: false` in jarl.yaml leaves
+`query-errors` alone; the page then can't show what rate limiting does.
+The Server options page lists this, and everything else Jarl adds to
+named.conf by itself, under **Added by Jarl** (`jarl option generated`).
 
 The statistics also count it: the `rrl` breakdown (`drop`, `slip`,
 `would-drop`, `would-slip`), the `ratelimited` and `ratelimited_name` top
@@ -160,6 +163,36 @@ external`). Set in the server options, it applies to every view that has
 none of its own, your internal resolver included, which RRL isn't meant
 for.
 
+## Mail
+
+Receivers such as Gmail and Outlook check the address mail comes from: it
+needs a PTR record (reverse DNS), and the name it gives must resolve back
+to the address. Without that, mail is rejected or marked as spam. The PTR
+records of your public addresses live in the reverse zones of whoever
+owns the addresses, your hosting provider or ISP: you set them in their
+panel, not in Jarl. A reverse zone you create in Jarl only answers your
+own clients (unless the owner delegated it to you).
+
+So Jarl checks them as the internet sees them, through the public
+resolvers of `acme.resolvers`: the addresses of every public zone's MX
+hosts (receiving) and SPF `ip4:`, `ip6:`, `a` and `a:` addresses
+(sending). The Exposure page's **Mail reverse DNS** panel shows each
+address, its PTR, who runs its reverse zone (the provider, from the
+zone's name server) and what to do; jarld checks a minute after it starts
+and every 6 hours, and logs an address that goes wrong.
+
+```
+$ jarl exposure mail
+ZONE         ADDRESS          FOR                           PTR               STATUS
+adbraun.lol  172.235.168.106  SPF ip4, MX mail.adbraun.lol  mail.adbraun.lol  ok
+```
+
+It warns when an address has no PTR record, or when its name doesn't
+resolve back to it; notes when the name is an alias (CNAME), or isn't the
+MX name (fine if the mail server uses it in HELO). `jarl exposure mail`
+exits 1 when an address isn't right; Prometheus has
+`jarl_mail_reverse_dns_ok{zone,address}`.
+
 ## Confirming a change that opens a view up
 
 A change that *introduces* an open resolver, open zone transfers, cache
@@ -204,7 +237,8 @@ monitoring, response size limits and usually a machine of its own.
 
 | Method | Path | Body |
 |--------|------|------|
-| GET | `/exposure` | `scopes` (per view, or the server: `public`, `override`, `reason`, `rate_limit` off/log-only/enforcing, `findings` with `fix` where Jarl has one), `server` (server-wide findings), `rate_limiting` (last 24h, with statistics: `counts`, `networks`, `names`) |
+| GET | `/exposure` | `scopes` (per view, or the server: `public`, `override`, `reason`, `rate_limit` off/log-only/enforcing, `findings` with `fix` where Jarl has one), `server` (server-wide findings), `rate_limiting` (last 24h, with statistics: `counts`, `networks`, `names`), `rate_limit_log`, `mail` (the last mail check) |
+| POST | `/exposure/mail` | Checks the mail addresses' reverse DNS now: `checked`, `results` (`zone`, `address`, `roles`, `ptr`, `ok`, `level` ok/info/warning, `message`, `reverse_zone`, `managed_by`, `local_zone`), `errors` |
 | POST | `/exposure/fix` | `{"view": "external", "code": "exposure_rate_limit"}` (`view_id` works too; no view: the server). Staged with `?changeset=` like any change |
 | POST | `/exposure/ack` | `{"view": "external", "code": "security_open_resolver", "reason": "..."}` |
 | POST | `/exposure/unack` | `{"view": "external", "code": "security_open_resolver"}` |

docs/metrics.md

@@ -132,6 +132,7 @@ same values.
 | `jarl_certificate_expiry_timestamp_seconds{certificate,source}` | When each certificate Jarl manages expires ([certificates.md](certificates.md)). |
 | `jarl_certificate_failing{certificate,source}` | 1 when obtaining (or reading) the certificate failed the last time, or it has expired. |
 | `jarl_certificate_renewal_failures{certificate}` | Failed attempts to obtain a certificate since its last success. |
+| `jarl_mail_reverse_dns_ok{zone,address}` | 1 when an address that sends or receives a public zone's mail has a PTR record that resolves back to it, at the last check, every 6 hours ([exposure.md](exposure.md#mail)). |
 | `jarl_encrypted_dns_up{kind,address,port}` | 1 when the DoT or DoH listener answered with the right, current certificate at the last check ([encrypted-dns.md](encrypted-dns.md#health)). |
 
 ### Queries (with `stats.enabled`)
@@ -238,6 +239,10 @@ groups:
         for: 20m
         annotations:
           summary: "DNS over {{ $labels.kind }} on {{ $labels.address }} port {{ $labels.port }} isn't working (see the Encrypted DNS page)"
+      - alert: MailReverseDNS
+        expr: jarl_mail_reverse_dns_ok == 0
+        annotations:
+          summary: "{{ $labels.address }} ({{ $labels.zone }} mail) has no reverse DNS that resolves back: receivers may reject its mail"
       - alert: BlockingPausedForLong
         expr: jarl_blocking_paused == 1
         for: 24h

docs/reverse.md

@@ -0,0 +1,163 @@
+# Reverse zones
+
+A reverse zone answers "which host has this address?" with PTR records:
+`20.10.0.10.in-addr.arpa. PTR nas.adbraun.lol.`. Your own clients use them
+for names in logs, `traceroute`, the router's client list and `ssh`
+warnings. For your private networks they only exist if this server has
+them, and they are easy to forget, so Jarl can work them out from the
+records you already have.
+
+Who asks matters:
+
+* **Your own clients** ask this server, so a reverse zone in a private
+  view (internal) answers them.
+* **The internet** asks whoever owns the address: your ISP or hosting
+  provider for public addresses. Mail servers check those PTR records, and
+  you set them in the provider's panel, not in Jarl. The Exposure page
+  checks them ([exposure.md](exposure.md#mail)). A reverse zone for a
+  public address in a public view (external) does nothing unless the owner
+  delegated it to you.
+
+So reverse zones belong in private views. A view whose clients reach it
+from the internet gets no suggestions, and neither does a view you turn
+them off for: a view only a few servers use, such as one for your VPS,
+matches only their addresses and so counts as private, but its clients
+don't need reverse zones (`jarl view update vps
+--reverse-suggestions=false`, or the view's settings). Exposure doesn't
+change.
+
+## Missing reverse zones
+
+The Zones page lists, under **Missing reverse zones**, the reverse zones a
+private view lacks for the addresses of its A and AAAA records, in two
+groups:
+
+```
+$ jarl zone suggest-reverse
+GROUP   VIEW      NETWORK                ZONE                              PTRS  FOR EXAMPLE
+yours   internal  10.0.10.0/24           10.0.10.in-addr.arpa              14    10.0.10.1 router.adbraun.lol, ...
+yours   internal  2a02:8013:7f3d::/48    d.3.f.7.3.1.0.8.2.0.a.2.ip6.arpa  9     2a02:8013:7f3d:10::5 nas.adbraun.lol, ...
+public  internal  139.144.144.154/32     154.144.144.139.in-addr.arpa      1     139.144.144.154 ldn.adbraun.lol
+public  internal  185.199.108.153/32     153.108.199.185.in-addr.arpa      1     185.199.108.153 blog.adbraun.lol
+
+$ jarl zone suggest-reverse --create                                        # yours, filled, in one changeset
+$ jarl zone create 139.144.144.154/32 --view internal --fill               # a public one that is yours
+$ jarl zone suggest-reverse --dismiss 185.199.108.153/32 --view internal   # GitHub's, not yours
+```
+
+**Yours**, created by **Create all** (`--create`):
+
+* the **/24** of a private IPv4 address (10/8, 172.16/12, 192.168/16,
+  100.64/10);
+* the **/48** of a ULA (fd00::/8), or of a public IPv6 prefix this server
+  has an address in (the /48 your ISP delegates): one zone for all its
+  subnets. If you have a /56, create that instead (`jarl zone create
+  2a02:db8:1:ab00::/56`).
+
+**Public addresses, only if they're yours**: any other public address,
+each as a /32 (or /128) of its own. Jarl can't tell your VPS from a web
+host's server (a `blog` record pointing at GitHub Pages), and a zone for
+someone else's address would show your clients your name for it instead
+of theirs. The rest of the /24 belongs to others: a /24 zone here would
+answer NXDOMAIN to your clients for all of their addresses. Create the
+ones that are yours one by one, and **Dismiss** the others: Jarl
+remembers, per view (`--undismiss` brings one back).
+
+There can be hundreds of public addresses (records pointing at a web
+host or a CDN), so the group is folded away when it is long. Opened, it
+has a search and shows 25 at a time; **Dismiss these N** dismisses every
+address the search found, in one change: search `104.16.` and dismiss
+the CDN's addresses together. From the CLI, `--dismiss` takes several
+networks (comma separated or repeated). The New reverse zone list has a
+search too.
+
+Loopback and link-local addresses, wildcards and disabled records are left
+out.
+
+## Creating one by hand
+
+Where nothing is suggested (a view with suggestions off, a dismissed
+network, a public view) or the suggested size isn't the one you want,
+**New reverse zone** on the Zones page lists every network your records
+use that has no reverse zone, in every view, marked when it isn't
+suggested unasked. Pick one: the network and the view are filled in.
+Then the **Size** buttons change it, around the address of one of the
+records: a suggested `2a02:8013:7f3d::/48` becomes
+`2a02:8013:7f3d:10::/64` for the subnet the records are in, or `/128`
+for one address. The zone name shows as you go, and **PTR records** stays
+ticked, so the zone is created with a PTR record for each address
+(IPv6 nibble names written for you).
+
+```sh
+jarl zone suggest-reverse --all --view vps                     # every network, hidden ones marked
+jarl zone create 2a02:8013:7f3d:10::/64 --view internal --fill
+```
+
+**Records in another view.** With a view chosen (`--view internal`, or
+the dialog's View), the list also has the addresses only other views'
+records use, marked "records in external": say a VPS's AAAA record that
+only the external view has. Fill names those from the other view's
+record, when the zone's own view has none for the address, and says so.
+Keeping PTR records in step (below) stays within a zone's own view and
+its linked views: a later change to that external record doesn't reach
+the internal reverse zone.
+
+## Creating and filling
+
+```sh
+jarl zone create 10.0.10.0/24 --fill       # the view whose records use 10.0.10.x
+jarl zone fill-ptr 10.0.10.0/24            # later: add what is missing
+```
+
+**The view.** A reverse zone created without `--view` goes to the private
+view whose records use addresses in its network (views with suggestions
+off don't count). If none does, it goes to the only private view. If
+several do, Jarl asks you to name the view, or to create the zone in each.
+
+**Inside another zone.** A zone created inside an existing one in the same
+view, a /24 inside a /8 or `lab.adbraun.lol` inside `adbraun.lol`, takes
+the parent's records under it, in the same changeset: named answers those
+names from the new zone, so left in the parent they would never be served
+again. PTR records you added by hand come along; `--fill` then adds only
+what is still missing. A delegation (NS records at the new zone's name,
+with their glue) stays in the parent. A linked parent keeps its records,
+with a warning, since its other views would lose them too.
+
+**Fill** adds a PTR record for every address in the network that the
+view's A and AAAA records use. An address with several names gets one PTR:
+
+1. the name of a mail or name server (an MX or NS target), else
+2. a host's name rather than the domain's own (`nas.adbraun.lol`, not
+   `adbraun.lol`), else
+3. the shortest name, then the first alphabetically.
+
+Jarl says which name it chose, and which it didn't, so you can change it.
+A reverse zone's page shows how many addresses still lack a PTR, with a
+button to add them. `jarl zone show` shows it as `Missing PTRs`.
+
+## Keeping PTR records in step
+
+The **Update PTR** box on an A or AAAA record (`--ptr`) moves the PTR record
+along with that one change. To have that on every change, turn it on for
+the forward zone:
+
+```sh
+jarl zone update adbraun.lol --view internal --auto-ptr          # off: --auto-ptr=false
+```
+
+(Zone settings → **Reverse DNS** in the web UI.) Then adding, changing,
+disabling, enabling or deleting an A or AAAA record in the zone does the
+same to its PTR record, in the reverse zones of the zone's view and of the
+views it is linked with ([views.md](views.md#linked-zones)). A whole set
+replaced at once (`jarl record set`, a batch) works too.
+
+* **One name per address.** When an address's PTR record names another
+  host, it stays: a second A record for the same address doesn't add a
+  second PTR record.
+* **No reverse zone, no PTR.** An address without a reverse zone in the
+  view, such as a public address in the external view, is skipped without
+  a warning. The suggestions above show what is missing.
+* **Wildcards** (`*.dev`) never get a PTR record.
+
+The PTR changes are part of the same changeset, so you review them, and
+they are applied or undone together with the record.

docs/stats.md

@@ -60,6 +60,7 @@ off again. The statistics database stays until you delete it
 stats:
   enabled: false
   query_log: true          # per-query data; false = named's counters only
+  rate_limit_log: true     # with a rate-limit: also log what it limits (query-errors)
   database: /var/lib/jarl/stats.db
   statistics_channel: 127.0.0.1:8058   # must be a loopback address
   log_file: /var/log/named/jarl-responses.log
@@ -81,6 +82,13 @@ the response log. Logging every answer costs named some CPU and disk I/O,
 which is negligible at homelab volumes. At tens of thousands of queries per
 second, consider counters only.
 
+`rate_limit_log` matters only with a `rate-limit` set: Jarl then sends
+named's `query-errors` category (where rate limiting logs what it limits,
+or would in log-only mode) to the response log too, and keeps it in
+syslog. That other query errors come along is the price; `false` stops it,
+and the Exposure page can't show rate limiting's activity then
+([exposure.md](exposure.md#response-rate-limiting)).
+
 `exclude_clients` drops those clients from the log-derived figures (top
 lists, views, zones). named's own counters can't be filtered.
 

docs/views.md

@@ -209,20 +209,6 @@ each view (Jarl lists them). Share the right version afterwards. Unlinking
 keeps every record, all local; a link left with one zone is dissolved, as
 when the other zone is deleted.
 
-**Comparing the views.** The zone's **Compare views** tab, or `jarl zone
-diff adbraun.lol`, lines the views up and shows each name and type that
-differs: a view's own records, or a name one view lacks. **Use this
-version** (`jarl record update ID --shared`) makes one view's version
-every view's. It works for zones that aren't linked too, to see what
-linking them would keep local.
-
-```
-$ jarl zone diff adbraun.lol
-NAME  TYPE  INTERNAL                    EXTERNAL
-nas   A     10.0.10.20 [local, id 812]  203.0.113.20 [local, id 790]
-5 names and types differ, 21 are the same; linked
-```
-
 `--local` also works on a zone that isn't linked (its records are local
 anyway), so scripts don't need to know; `--shared` there is refused.
 
@@ -246,6 +232,54 @@ as it is: linked zones can differ per view, keep their own options, and
 don't depend on the view order (`in-view` can only use a view defined
 before it).
 
+## Comparing views
+
+A zone's **Compare views** tab, or `jarl zone diff`, compares it with the
+same zone in another view (or all of them), from the view you're on:
+
+```
+$ jarl zone diff adbraun.lol --view internal
+adbraun.lol in internal, compared with external
+  linked: a difference is a view's own records, there on purpose
+  external: 1 answered differently, 24 only in internal, 2 only in external, 31 the same
+
+ANSWERED DIFFERENTLY (1)
+  nas A
+    internal  10.0.10.20    [local, id 812]
+    external  203.0.113.20  [local, id 790]
+
+ONLY IN INTERNAL (24)
+  printer A  10.0.10.30
+  router A   10.0.10.1
+  ...
+
+ONLY IN EXTERNAL (2)
+  _acme-challenge TXT  "…"
+  ...
+
+31 names and types are the same (--all lists them)
+```
+
+* **Answered differently**: names and types more than one view has, with
+  different records. In linked zones that is a view's own (local)
+  records, there on purpose; between zones that aren't linked, it is a
+  difference that crept in. **Use this everywhere** gives every view one
+  view's records (in linked zones by sharing them: `jarl record update ID
+  --shared`).
+* **Only in …**: names and types some views lack. **Add to external**
+  gives that view the same records, its own.
+* **The same**: how many; `--all` (or "List them") shows them.
+
+One line per record: the CLI cuts long values to fit the terminal
+(`--wide` shows them whole); the web UI shows the whole value on hover.
+The apex NS records are left out, since views often list their name
+servers differently on purpose.
+
+**One name.** `jarl zone diff adbraun.lol nas` (and a type: `... @ TXT`)
+shows just that name in every view, the same records included. In the
+web UI, a record's **Compare** button does the same. `--with external`
+(repeat it) picks the views to compare with.
+
 ## Living with views
 
 * Commands that name a zone that exists in several views need `--view`

internal/api/types.go

@@ -37,6 +37,11 @@ type Zone struct {
 	// OtherViews are the other views with a primary zone of this name
 	// (linked or not): what GET /zones/{zone}/compare compares.
 	OtherViews []string `json:"other_views,omitempty"`
+	// Prefix is the network a reverse zone answers for; PTRMissing how
+	// many of its view's A and AAAA addresses in it have no PTR record
+	// (POST /zones/{zone}/fill-ptr adds them).
+	Prefix     string `json:"prefix,omitempty"`
+	PTRMissing int    `json:"ptr_missing,omitempty"`
 	// Pending is set when listing with a changeset: add, change or delete.
 	Pending string `json:"pending,omitempty"`
 }

internal/config/config.go

@@ -364,6 +364,10 @@ type Stats struct {
 	// per-zone counts) from named's response log. Without it only named's
 	// own counters are collected.
 	QueryLog bool `yaml:"query_log"`
+	// RateLimitLog sends rate limiting's log lines (named's query-errors
+	// category) to the response log too, so the Exposure page and the
+	// statistics can show what was, or would be, limited.
+	RateLimitLog bool `yaml:"rate_limit_log"`
 	// Database is the statistics database, kept apart from Jarl's
 	// configuration database.
 	Database string `yaml:"database"`
@@ -451,6 +455,7 @@ func Default() *Config {
 		},
 		Stats: Stats{
 			QueryLog:          true,
+			RateLimitLog:      true,
 			Database:          "/var/lib/jarl/stats.db",
 			StatisticsChannel: "127.0.0.1:8058",
 			LogFile:           "/var/log/named/jarl-responses.log",
@@ -736,6 +741,10 @@ stats:
   # Per-query data (top names and clients, per view and zone). false
   # collects only named's own counters, with no logging overhead.
   query_log: true
+  # With a rate-limit set, also log what rate limiting limits (or would,
+  # in log-only mode): named's query-errors category, which Jarl then adds
+  # to its log channel (and keeps in syslog). The Exposure page shows it.
+  rate_limit_log: true
   database: /var/lib/jarl/stats.db
   statistics_channel: 127.0.0.1:8058
   log_file: /var/log/named/jarl-responses.log

internal/dnsname/dnsname.go

@@ -469,3 +469,47 @@ func BestZone(name string, zones []string) string {
 	}
 	return best
 }
+
+// PrefixFromReverse returns the network a reverse zone answers for:
+// 10.0.10.in-addr.arpa. is 10.0.10.0/24, a /32 zone a single address, and
+// an ip6.arpa zone of 12 nibbles a /48. False for names that aren't whole
+// octets or nibbles (classless delegations such as 0-63.1.0.10.in-addr.arpa.).
+func PrefixFromReverse(zone string) (netip.Prefix, bool) {
+	zone = strings.ToLower(Fqdn(zone))
+	switch {
+	case strings.HasSuffix(zone, ".in-addr.arpa."):
+		labels := strings.Split(strings.TrimSuffix(zone, ".in-addr.arpa."), ".")
+		if len(labels) > 4 {
+			return netip.Prefix{}, false
+		}
+		var b [4]byte
+		for i, l := range labels {
+			v, err := strconv.Atoi(l)
+			if err != nil || v < 0 || v > 255 || strconv.Itoa(v) != l {
+				return netip.Prefix{}, false
+			}
+			b[len(labels)-1-i] = byte(v)
+		}
+		return netip.PrefixFrom(netip.AddrFrom4(b), 8*len(labels)), true
+	case strings.HasSuffix(zone, ".ip6.arpa."):
+		labels := strings.Split(strings.TrimSuffix(zone, ".ip6.arpa."), ".")
+		if len(labels) > 32 {
+			return netip.Prefix{}, false
+		}
+		var b [16]byte
+		for i, l := range labels {
+			v := strings.IndexByte("0123456789abcdef", l[0])
+			if len(l) != 1 || v < 0 {
+				return netip.Prefix{}, false
+			}
+			n := len(labels) - 1 - i // nibble position from the left
+			if n%2 == 0 {
+				b[n/2] |= byte(v) << 4
+			} else {
+				b[n/2] |= byte(v)
+			}
+		}
+		return netip.PrefixFrom(netip.AddrFrom16(b), 4*len(labels)), true
+	}
+	return netip.Prefix{}, false
+}

internal/dnsname/dnsname_test.go

@@ -217,3 +217,35 @@ func TestReverseZones(t *testing.T) {
 		t.Errorf("ReverseZone /22: %v", err)
 	}
 }
+
+func TestPrefixFromReverse(t *testing.T) {
+	for zone, want := range map[string]string{
+		"10.0.10.in-addr.arpa.":             "10.0.10.0/24",
+		"10.in-addr.arpa":                   "10.0.0.0/8",
+		"154.144.144.139.in-addr.arpa.":     "139.144.144.154/32",
+		"d.3.f.7.3.1.0.8.2.0.a.2.ip6.arpa.": "2a02:8013:7f3d::/48",
+		"b.a.b.a.b.a.b.a.b.a.d.f.ip6.arpa.": "fdab:abab:abab::/48",
+		"0-63.1.0.10.in-addr.arpa.":         "",
+		"example.com.":                      "",
+		"256.10.in-addr.arpa.":              "",
+	} {
+		p, ok := PrefixFromReverse(zone)
+		got := ""
+		if ok {
+			got = p.String()
+		}
+		if got != want {
+			t.Errorf("PrefixFromReverse(%q) = %q, want %q", zone, got, want)
+		}
+	}
+	// Round trip with ReverseZone.
+	for _, s := range []string{"192.168.1.0/24", "2a02:8013:7f3d::/48", "fd00::/8", "10.0.0.5/32"} {
+		z, err := ReverseZone(netip.MustParsePrefix(s))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if p, ok := PrefixFromReverse(z); !ok || p.String() != s {
+			t.Errorf("%s -> %s -> %v", s, z, p)
+		}
+	}
+}

internal/engine/compare.go

@@ -5,6 +5,7 @@ import (
 	"slices"
 	"strings"
 
+	"jarl/internal/dnsname"
 	"jarl/internal/model"
 )
 
@@ -14,6 +15,8 @@ type ViewSet struct {
 	ZoneID  int64    `json:"zone_id"`
 	Records []string `json:"records"`          // data (with TTL and "(disabled)" when set), sorted
 	IDs     []int64  `json:"ids"`              // the records, in the same order
+	Data    []string `json:"data"`             // their data alone, in the same order
+	TTL     *uint32  `json:"ttl,omitempty"`    // the first record's own TTL
 	Linked  string   `json:"linked,omitempty"` // shared or local, in a linked zone
 }
 
@@ -63,7 +66,7 @@ func CompareZones(st *model.State, zones []*model.Zone) []CompareRow {
 		}
 		var first string
 		for i, z := range zones {
-			vs := ViewSet{View: st.ViewName(z), ZoneID: z.ID, Records: []string{}, IDs: []int64{}}
+			vs := ViewSet{View: st.ViewName(z), ZoneID: z.ID, Records: []string{}, IDs: []int64{}, Data: []string{}}
 			rs := slices.Clone(sets[i][k])
 			slices.SortFunc(rs, func(a, b *model.Record) int { return strings.Compare(strings.ToLower(a.Data), strings.ToLower(b.Data)) })
 			for _, r := range rs {
@@ -76,6 +79,10 @@ func CompareZones(st *model.State, zones []*model.Zone) []CompareRow {
 				}
 				vs.Records = append(vs.Records, d)
 				vs.IDs = append(vs.IDs, r.ID)
+				vs.Data = append(vs.Data, r.Data)
+				if vs.TTL == nil && r.TTL != nil {
+					vs.TTL = model.Ptr(*r.TTL)
+				}
 			}
 			if z.LinkGroup != 0 && len(rs) > 0 {
 				vs.Linked = "shared"
@@ -102,3 +109,128 @@ func relName(name, zone string) string {
 	}
 	return strings.TrimSuffix(name, "."+zone)
 }
+
+// CompareReport is a zone in one view (the base) next to the same zone in
+// other views (docs/views.md#comparing-views): what the other views answer
+// differently, the names only some views have, and how much is the same.
+type CompareReport struct {
+	Zone   string   `json:"zone"`
+	Base   string   `json:"base"`   // the view compared from
+	Views  []string `json:"views"`  // the base first
+	Linked bool     `json:"linked"` // all in one link
+	// Summary is, per other view, how it differs from the base.
+	Summary []CompareSummary `json:"summary"`
+	// Different are names and types more than one view has, with
+	// different records.
+	Different []CompareRow `json:"different"`
+	// Only are the names and types only some views have, by the views
+	// that have them.
+	Only []CompareOnly `json:"only"`
+	Same int           `json:"same"`
+	// SameRows are the ones that are the same (when asked for).
+	SameRows []CompareRow `json:"same_rows,omitempty"`
+}
+
+// CompareSummary counts how a view differs from the base view.
+type CompareSummary struct {
+	View      string `json:"view"`
+	Different int    `json:"different"`  // both have it, with different records
+	OnlyBase  int    `json:"only_base"`  // the base has it, this view doesn't
+	OnlyOther int    `json:"only_other"` // this view has it, the base doesn't
+	Same      int    `json:"same"`
+}
+
+// CompareOnly are names and types that only some views have.
+type CompareOnly struct {
+	Views []string     `json:"views"`
+	Rows  []CompareRow `json:"rows"`
+}
+
+// CompareFilter narrows a comparison to a name, and optionally a type.
+type CompareFilter struct {
+	Name string // relative ("www", "@") or absolute
+	Type string
+	All  bool // include what is the same
+}
+
+// Compare builds the report for zones (the base first). Apex NS records are
+// left out: they name the servers, which views often list differently on
+// purpose.
+func Compare(st *model.State, zones []*model.Zone, f CompareFilter) *CompareReport {
+	rep := &CompareReport{Zone: dnsname.Display(zones[0].Name), Base: st.ViewName(zones[0]), Different: []CompareRow{}, Only: []CompareOnly{}, Linked: true}
+	for _, z := range zones {
+		rep.Views = append(rep.Views, st.ViewName(z))
+		rep.Linked = rep.Linked && z.LinkGroup != 0 && z.LinkGroup == zones[0].LinkGroup
+	}
+	for _, v := range rep.Views[1:] {
+		rep.Summary = append(rep.Summary, CompareSummary{View: v})
+	}
+	want := ""
+	if f.Name != "" {
+		if o, err := dnsname.Owner(f.Name, zones[0].Name); err == nil {
+			want = o
+		}
+	}
+	only := map[string]int{}
+	for _, row := range CompareZones(st, zones) {
+		if row.FQDN == zones[0].Name && row.Type == "NS" {
+			continue
+		}
+		if want != "" && (row.FQDN != want || f.Type != "" && !strings.EqualFold(row.Type, f.Type)) {
+			continue
+		}
+		base := row.Views[0]
+		for i, vs := range row.Views[1:] {
+			s := &rep.Summary[i]
+			switch {
+			case len(base.Records) > 0 && len(vs.Records) > 0 && slices.Equal(base.Records, vs.Records):
+				s.Same++
+			case len(base.Records) > 0 && len(vs.Records) > 0:
+				s.Different++
+			case len(base.Records) > 0:
+				s.OnlyBase++
+			case len(vs.Records) > 0:
+				s.OnlyOther++
+			}
+		}
+		if row.Same {
+			rep.Same++
+			if f.All || want != "" {
+				rep.SameRows = append(rep.SameRows, row)
+			}
+			continue
+		}
+		var having []string
+		versions := map[string]bool{}
+		for _, vs := range row.Views {
+			if len(vs.Records) > 0 {
+				having = append(having, vs.View)
+				versions[strings.Join(vs.Records, "\n")] = true
+			}
+		}
+		if len(versions) > 1 {
+			rep.Different = append(rep.Different, row)
+			continue
+		}
+		k := strings.Join(having, ",")
+		i, ok := only[k]
+		if !ok {
+			i = len(rep.Only)
+			only[k] = i
+			rep.Only = append(rep.Only, CompareOnly{Views: having})
+		}
+		rep.Only[i].Rows = append(rep.Only[i].Rows, row)
+	}
+	// The base's own names first, then by how many views have them.
+	slices.SortStableFunc(rep.Only, func(a, b CompareOnly) int {
+		ab, bb := slices.Contains(a.Views, rep.Base), slices.Contains(b.Views, rep.Base)
+		if ab != bb {
+			if ab {
+				return -1
+			}
+			return 1
+		}
+		return len(b.Views) - len(a.Views)
+	})
+	return rep
+}

internal/engine/diffops.go

@@ -25,7 +25,7 @@ func DiffOps(from, to *model.State) []model.Op {
 		s := to.Settings
 		add(OpSettingsUpdate, 0, 0, SettingsInput{DefaultTTL: &s.DefaultTTL, Nameservers: model.Ptr(append([]string{}, s.Nameservers...)), RName: &s.RName,
 			Refresh: &s.Refresh, Retry: &s.Retry, Expire: &s.Expire, NegativeTTL: &s.NegativeTTL, SerialPolicy: &s.SerialPolicy,
-			Exposure: &s.Exposure, Acknowledged: model.Ptr(slices.Clone(s.Acknowledged))}, "restore settings")
+			Exposure: &s.Exposure, Acknowledged: model.Ptr(slices.Clone(s.Acknowledged)), DismissedReverse: model.Ptr(slices.Clone(s.DismissedReverse))}, "restore settings")
 	}
 
 	for _, k := range sortedKeys(to.Keys) {
@@ -50,7 +50,8 @@ func DiffOps(from, to *model.State) []model.Op {
 		n := to.Views[k]
 		in := ViewInput{Name: &n.Name, MatchClients: model.Ptr(append([]string{}, n.MatchClients...)),
 			MatchDestinations: model.Ptr(append([]string{}, n.MatchDestinations...)), Comment: &n.Comment, Position: model.Ptr(n.Position),
-			Exposure: model.Ptr(n.Exposure), Acknowledged: model.Ptr(slices.Clone(n.Acknowledged))}
+			Exposure: model.Ptr(n.Exposure), Acknowledged: model.Ptr(slices.Clone(n.Acknowledged)),
+			ReverseSuggestions: model.Ptr(!n.ReverseSuggestionsOff), DismissedReverse: model.Ptr(slices.Clone(n.DismissedReverse))}
 		if n.MatchRecursiveOnly != nil {
 			in.MatchRecursiveOnly = model.Some(*n.MatchRecursiveOnly)
 		} else {
@@ -66,7 +67,7 @@ func DiffOps(from, to *model.State) []model.Op {
 		n := to.Zones[k]
 		s := n.SOA
 		in := ZoneInput{Name: &n.Name, ViewID: &n.ViewID, Type: &n.Type, InView: &n.InView, File: &n.File,
-			DefaultTTL: &n.DefaultTTL, SerialPolicy: &n.SerialPolicy, DNSSECPolicy: &n.DNSSECPolicy, Comment: &n.Comment, Disabled: &n.Disabled, LinkGroup: model.Ptr(n.LinkGroup)}
+			DefaultTTL: &n.DefaultTTL, SerialPolicy: &n.SerialPolicy, DNSSECPolicy: &n.DNSSECPolicy, Comment: &n.Comment, Disabled: &n.Disabled, LinkGroup: model.Ptr(n.LinkGroup), AutoPTR: model.Ptr(n.AutoPTR)}
 		if n.Type == model.ZonePrimary {
 			in.SOA = &SOAInput{MName: &s.MName, RName: &s.RName, Serial: &s.Serial, Refresh: &s.Refresh, Retry: &s.Retry, Expire: &s.Expire, Minimum: &s.Minimum}
 		}

internal/engine/engine.go

@@ -285,7 +285,7 @@ func (e *Engine) expandAll(ctx context.Context, work *model.State, reqs []Reques
 	var warnings []string
 	c := &applyCtx{p: p, now: e.Now()}
 	for i, req := range reqs {
-		x := &expander{ctx: ctx, st: work, alloc: e.store.AllocateIDs, p: p, now: e.Now()}
+		x := &expander{ctx: ctx, st: work, alloc: e.store.AllocateIDs, p: p, now: e.Now(), exposures: e.Exposures}
 		more, err := x.expand(req)
 		if err != nil {
 			if ee, ok := AsError(err); ok && len(reqs) > 1 {

internal/engine/expand.go

@@ -28,6 +28,9 @@ type expander struct {
 	p        *auth.Principal
 	now      time.Time
 	warnings []string
+	// exposures classifies the views as public or private (nil in tests:
+	// every view private).
+	exposures func(*model.State) []validate.Exposure
 }
 
 func (x *expander) ids(n int) ([]int64, error) {
@@ -137,7 +140,7 @@ func (x *expander) expand(req Request) ([]model.Op, error) {
 		return nil, err
 	}
 	switch req.Op {
-	case OpRecordCreate, OpRecordUpdate, OpRecordDelete, OpRRSetReplace, OpRecordDisable, OpRecordEnable:
+	case OpRecordCreate, OpRecordUpdate, OpRecordDelete, OpRRSetReplace, OpRecordDisable, OpRecordEnable, OpZoneFillPTR:
 		// Changes to linked zones reach the other zones of the link.
 		return x.linkSync(ops)
 	}
@@ -152,6 +155,10 @@ func (x *expander) expandOne(req Request) ([]model.Op, error) {
 		return x.zoneUnlink(req)
 	case OpZoneCreate:
 		return x.zoneCreate(req)
+	case OpZoneFillPTR:
+		return x.zoneFillPTR(req)
+	case OpReverseDismiss, OpReverseUndismiss:
+		return x.reverseDismiss(req, req.Op == OpReverseDismiss)
 	case OpZoneUpdate, OpZoneDelete:
 		z := x.st.Zones[req.ID]
 		if z == nil {
@@ -376,6 +383,7 @@ func (x *expander) zoneCreate(req Request) ([]model.Op, error) {
 		return nil, errf(KindBadRequest, "%v", err)
 	}
 	in.Type = &zt
+	viewGiven := in.View != nil || in.ViewID != nil
 	if in.View != nil {
 		if *in.View != "" {
 			v := x.st.ViewByName(*in.View)
@@ -386,6 +394,74 @@ func (x *expander) zoneCreate(req Request) ([]model.Op, error) {
 		}
 		in.View = nil
 	}
+	if !viewGiven && in.LinkWith == "" && in.CloneFrom == 0 && dnsname.IsReverse(name) {
+		// A reverse zone belongs in the private view whose records use
+		// its addresses (docs/reverse.md).
+		v, err := reverseViewFor(x.st, x.publicViews(), name)
+		if err != nil {
+			return nil, err
+		}
+		if v != nil {
+			in.ViewID = &v.ID
+		}
+	}
+	var moveOps []model.Op
+	var moved []*model.Record
+	if zt == model.ZonePrimary {
+		// The records a parent zone in the view has under the new zone
+		// move into it: named answers those names from the new zone, so
+		// left behind they would never be served again.
+		vid := int64(0)
+		if in.ViewID != nil {
+			vid = *in.ViewID
+		}
+		if parent := x.parentZone(name, vid); parent != nil {
+			moved = x.recordsUnder(parent, name)
+			switch {
+			case len(moved) == 0:
+			case parent.LinkGroup != 0:
+				x.warnings = append(x.warnings, fmt.Sprintf("zone %s is linked, so its %d records under %s stay there (hidden by the new zone): move them by hand", zoneDesc(x.st, parent), len(moved), dnsname.Display(name)))
+				moved = nil
+			default:
+				for _, r := range moved {
+					ri := RecordInput{Name: model.Ptr(r.Name), Type: model.Ptr(r.Type), Data: model.Ptr(r.Data)}
+					if r.TTL != nil {
+						ri.TTL = model.Some(*r.TTL)
+					}
+					if r.Comment != "" {
+						ri.Comment = model.Ptr(r.Comment)
+					}
+					if r.Disabled {
+						ri.Disabled = model.Ptr(true)
+					}
+					in.Records = append(in.Records, ri)
+					moveOps = append(moveOps, newOp(OpRecordDelete, r.ID, r.Version, nil, fmt.Sprintf("move %s %s %s from zone %s into the new zone", r.Name, r.Type, r.Data, zoneDesc(x.st, parent))))
+				}
+			}
+		}
+	}
+	fill := in.Fill
+	in.Fill = false
+	if fill {
+		if zt != model.ZonePrimary {
+			return nil, errf(KindBadRequest, "fill only applies to primary zones")
+		}
+		if _, ok := dnsname.PrefixFromReverse(name); !ok {
+			return nil, errf(KindBadRequest, "fill only applies to reverse zones of whole octets or nibbles (like 10.0.10.0/24)")
+		}
+		vid := int64(0)
+		if in.ViewID != nil {
+			vid = *in.ViewID
+		}
+		fills := PTRFills(x.st, vid, name, moved)
+		if len(fills) == 0 {
+			x.warnings = append(x.warnings, fmt.Sprintf("no A or AAAA record of %s has an address in %s, so there was nothing to fill it with", viewOrServer(x.st, vid), dnsname.Display(name)))
+		}
+		x.warnings = append(x.warnings, fillWarnings(fills)...)
+		for _, f := range fills {
+			in.Records = append(in.Records, RecordInput{Name: model.Ptr(f.Name), Type: model.Ptr("PTR"), Data: model.Ptr(f.Target)})
+		}
+	}
 	nameservers := in.Nameservers
 	records := in.Records
 	cloneFrom := in.CloneFrom
@@ -603,7 +679,45 @@ func (x *expander) zoneCreate(req Request) ([]model.Op, error) {
 		r.in.ZoneID = ids[0]
 		ops = append(ops, newOp(OpRecordCreate, ids[1+i], 0, r.in, r.summary))
 	}
-	return ops, nil
+	return append(ops, moveOps...), nil
+}
+
+// parentZone returns the most specific primary zone in a view that
+// contains name (not name itself).
+func (x *expander) parentZone(name string, viewID int64) *model.Zone {
+	var best *model.Zone
+	for _, z := range x.st.ZonesInView(viewID) {
+		if z.Type == model.ZonePrimary && dnsname.IsStrictSubdomain(name, z.Name) && (best == nil || len(z.Name) > len(best.Name)) {
+			best = z
+		}
+	}
+	return best
+}
+
+// recordsUnder returns a zone's records at or below name, except a
+// delegation's NS and DS records and its glue, which belong to the parent.
+func (x *expander) recordsUnder(z *model.Zone, name string) []*model.Record {
+	all := x.st.ZoneRecords(z.ID)
+	var ns []string
+	for _, r := range all {
+		if r.Name == name && r.Type == "NS" {
+			ns = append(ns, strings.ToLower(r.Data))
+		}
+	}
+	var out []*model.Record
+	for _, r := range all {
+		if !dnsname.IsSubdomain(r.Name, name) {
+			continue
+		}
+		if r.Name == name && (r.Type == "NS" || r.Type == "DS") {
+			continue
+		}
+		if (r.Type == "A" || r.Type == "AAAA") && slices.Contains(ns, strings.ToLower(r.Name)) {
+			continue // glue
+		}
+		out = append(out, r)
+	}
+	return out
 }
 
 func deref(s *string) string {
@@ -638,7 +752,11 @@ func addrOf(p *rr.Parsed) (netip.Addr, bool) {
 }
 
 // ptrOps returns operations creating the PTR record for an address record.
-func (x *expander) ptrCreate(z *model.Zone, owner string, p *rr.Parsed) ([]model.Op, error) {
+//
+// auto is set when the zone's auto_ptr asked rather than the request: a
+// missing reverse zone isn't worth a warning then (most addresses have
+// none), and an address whose PTR record names another host keeps it.
+func (x *expander) ptrCreate(z *model.Zone, owner string, p *rr.Parsed, auto bool) ([]model.Op, error) {
 	addr, ok := addrOf(p)
 	if !ok {
 		return nil, errf(KindBadRequest, "ptr only applies to A and AAAA records")
@@ -651,13 +769,13 @@ func (x *expander) ptrCreate(z *model.Zone, owner string, p *rr.Parsed) ([]model
 			continue
 		}
 		found = true
-		more, err := x.ptrCreateIn(rz, ptrName, owner)
+		more, err := x.ptrCreateIn(rz, ptrName, owner, auto)
 		if err != nil {
 			return nil, err
 		}
 		ops = append(ops, more...)
 	}
-	if !found {
+	if !found && !auto {
 		x.warnings = append(x.warnings, fmt.Sprintf("no reverse zone for %s in this view, so no PTR record was added (create one: jarl zone create %s/%d)", addr, addr, addr.BitLen()))
 	}
 	return ops, nil
@@ -678,7 +796,8 @@ func ptrViews(st *model.State, z *model.Zone) []int64 {
 
 // ptrCreateIn returns operations creating the PTR record ptrName -> owner
 // in reverse zone rz (none when it is there; enabling it when disabled).
-func (x *expander) ptrCreateIn(rz *model.Zone, ptrName, owner string) ([]model.Op, error) {
+func (x *expander) ptrCreateIn(rz *model.Zone, ptrName, owner string, auto bool) ([]model.Op, error) {
+	var other string
 	for _, r := range x.st.ZoneRecords(rz.ID) {
 		if r.Name == ptrName && r.Type == "PTR" {
 			if strings.EqualFold(r.Data, owner) {
@@ -688,9 +807,18 @@ func (x *expander) ptrCreateIn(rz *model.Zone, ptrName, owner string) ([]model.O
 				}
 				return nil, nil // already there
 			}
-			x.warnings = append(x.warnings, fmt.Sprintf("%s already has a PTR record (%s); adding another one", ptrName, r.Data))
+			if !r.Disabled {
+				other = r.Data
+			}
 		}
 	}
+	if other != "" {
+		if auto {
+			// One name per address: the one it has stays.
+			return nil, nil
+		}
+		x.warnings = append(x.warnings, fmt.Sprintf("%s already has a PTR record (%s); adding another one", ptrName, other))
+	}
 	ids, err := x.ids(1)
 	if err != nil {
 		return nil, err
@@ -778,7 +906,7 @@ func (x *expander) recordCreate(req Request) ([]model.Op, error) {
 		return nil, err
 	}
 	x.parseWarnings(owner, p)
-	ptr := in.PTR
+	ptr, auto := in.PTR, !in.PTR && autoPTR(z, owner, p)
 	in.ZoneID, in.Zone, in.View, in.PTR = z.ID, "", "", false
 	in.Name, in.Type, in.Data = &owner, &p.Type, &p.Data
 	ids, err := x.ids(1)
@@ -807,8 +935,8 @@ func (x *expander) recordCreate(req Request) ([]model.Op, error) {
 	// local on a zone that isn't linked: its records are local anyway.
 	in.Local = nil
 	ops := []model.Op{newOp(OpRecordCreate, ids[0], 0, in, summary)}
-	if ptr {
-		more, err := x.ptrCreate(z, owner, p)
+	if ptr || auto && (in.Disabled == nil || !*in.Disabled) {
+		more, err := x.ptrCreate(z, owner, p, auto)
 		if err != nil {
 			return nil, err
 		}
@@ -939,13 +1067,43 @@ func (x *expander) recordUpdate(req Request) ([]model.Op, error) {
 	if in.Disabled != nil {
 		disabled = *in.Disabled
 	}
-	moved := p.Data != r.Data || owner != r.Name
+	moved := p.Data != r.Data || owner != r.Name || p.Type != r.Type
+	if !ptr && z.AutoPTR {
+		// The zone keeps PTR records in step (docs/reverse.md): as if
+		// asked, for whichever of the old and new record is an address.
+		old, err := rr.Parse(z.Name, r.Name, r.Type, r.Data)
+		oldAuto := err == nil && autoPTR(z, r.Name, old)
+		newAuto := autoPTR(z, owner, p)
+		switch {
+		case moved:
+			if oldAuto {
+				ops = append(ops, x.ptrDelete(z, r.Name, old)...)
+			}
+			if newAuto && !disabled {
+				more, err := x.ptrCreate(z, owner, p, true)
+				if err != nil {
+					return nil, err
+				}
+				ops = append(ops, more...)
+			}
+		case toggled && newAuto && disabled:
+			ops = append(ops, x.ptrSetDisabled(z, owner, p, true)...)
+		case toggled && newAuto:
+			// Enables the PTR record, or adds it when it is missing.
+			more, err := x.ptrCreate(z, owner, p, true)
+			if err != nil {
+				return nil, err
+			}
+			ops = append(ops, more...)
+		}
+		return ops, nil
+	}
 	if ptr && moved {
 		if old, err := rr.Parse(z.Name, r.Name, r.Type, r.Data); err == nil {
 			ops = append(ops, x.ptrDelete(z, r.Name, old)...)
 		}
 		if !disabled {
-			more, err := x.ptrCreate(z, owner, p)
+			more, err := x.ptrCreate(z, owner, p, false)
 			if err != nil {
 				return nil, err
 			}
@@ -961,7 +1119,7 @@ func (x *expander) recordUpdate(req Request) ([]model.Op, error) {
 	if ptr && !moved && !toggled && !disabled {
 		// Nothing else changes: make sure the PTR record is there (the
 		// reverse zone may be newer than the record).
-		more, err := x.ptrCreate(z, owner, p)
+		more, err := x.ptrCreate(z, owner, p, false)
 		if err != nil {
 			return nil, err
 		}
@@ -988,11 +1146,9 @@ func (x *expander) recordDelete(req Request) ([]model.Op, error) {
 			base = r.Version
 		}
 		ops := []model.Op{newOp(OpRecordDelete, r.ID, base, nil, fmt.Sprintf("delete %s %s %s", r.Name, r.Type, r.Data))}
-		if in.PTR {
-			z := x.st.Zones[r.ZoneID]
-			if p, err := rr.Parse(z.Name, r.Name, r.Type, r.Data); err == nil {
-				ops = append(ops, x.ptrDelete(z, r.Name, p)...)
-			}
+		z := x.st.Zones[r.ZoneID]
+		if p, err := rr.Parse(z.Name, r.Name, r.Type, r.Data); err == nil && (in.PTR || autoPTR(z, r.Name, p)) {
+			ops = append(ops, x.ptrDelete(z, r.Name, p)...)
 		}
 		return ops, nil
 	}
@@ -1032,8 +1188,19 @@ func (x *expander) recordDelete(req Request) ([]model.Op, error) {
 	in.ZoneID, in.Zone, in.View, in.PTR = z.ID, "", "", false
 	in.Name, in.Type = &owner, &typ
 	ops := []model.Op{newOp(OpRecordDelete, 0, 0, in, "delete "+what)}
-	if ptr && parsed != nil {
+	switch {
+	case ptr && parsed != nil:
 		ops = append(ops, x.ptrDelete(z, owner, parsed)...)
+	case z.AutoPTR:
+		// Every matching record's PTR record goes too.
+		for _, r := range x.st.RRset(z.ID, owner, typ) {
+			if parsed != nil && r.Data != parsed.Data {
+				continue
+			}
+			if p, err := rr.Parse(z.Name, r.Name, r.Type, r.Data); err == nil && autoPTR(z, r.Name, p) {
+				ops = append(ops, x.ptrDelete(z, r.Name, p)...)
+			}
+		}
 	}
 	return ops, nil
 }
@@ -1169,7 +1336,32 @@ func (x *expander) rrsetReplace(req Request) ([]model.Op, error) {
 	if len(canon) == 0 {
 		summary = fmt.Sprintf("delete all %s records of %s%s", typ, owner, where)
 	}
-	return append(pre, newOp(OpRRSetReplace, 0, 0, in, summary)), nil
+	ops := append(pre, newOp(OpRRSetReplace, 0, 0, in, summary))
+	if z.AutoPTR && (typ == "A" || typ == "AAAA") && !strings.HasPrefix(owner, "*.") {
+		// PTR records follow the addresses that go and come.
+		old := map[string]bool{}
+		for _, r := range x.st.RRset(z.ID, owner, typ) {
+			old[r.Data] = true
+			if !slices.Contains(canon, r.Data) {
+				if p, err := rr.Parse(z.Name, r.Name, r.Type, r.Data); err == nil {
+					ops = append(ops, x.ptrDelete(z, r.Name, p)...)
+				}
+			}
+		}
+		for _, d := range canon {
+			if old[d] {
+				continue
+			}
+			if _, p, err := parseRecord(z, owner, typ, d); err == nil {
+				more, err := x.ptrCreate(z, owner, p, true)
+				if err != nil {
+					return nil, err
+				}
+				ops = append(ops, more...)
+			}
+		}
+	}
+	return ops, nil
 }
 
 func (x *expander) viewCreate(req Request) ([]model.Op, error) {

internal/engine/inputs.go

@@ -59,8 +59,25 @@ const (
 	// into zone and record updates.
 	OpZoneLink   = "zone.link"
 	OpZoneUnlink = "zone.unlink"
+	// Filling a reverse zone with the PTR records of its view's A and
+	// AAAA records (docs/reverse.md) becomes record.create operations.
+	OpZoneFillPTR = "zone.fill_ptr"
+	// Dismissing a reverse zone suggestion, and taking that back, become
+	// view.update or settings.update operations.
+	OpReverseDismiss   = "reverse.dismiss"
+	OpReverseUndismiss = "reverse.undismiss"
 )
 
+// DismissInput dismisses a reverse zone suggestion: a network in a view
+// (by ID or name), or the server's (neither given).
+type DismissInput struct {
+	ViewID int64  `json:"view_id,omitempty"`
+	View   string `json:"view,omitempty"`
+	Prefix string `json:"prefix,omitempty"`
+	// Prefixes dismisses (or brings back) several at once.
+	Prefixes []string `json:"prefixes,omitempty"`
+}
+
 // AckInput acknowledges (or un-acknowledges) an exposure finding of a view
 // (by ID or name), or of the server (neither given).
 type AckInput struct {
@@ -142,6 +159,12 @@ type ZoneInput struct {
 	// name in this view, copying its shared records (or all of its
 	// records, when it isn't linked yet).
 	LinkWith string `json:"link_with,omitempty"`
+	// AutoPTR keeps the PTR records of the zone's A and AAAA records in
+	// step (docs/reverse.md).
+	AutoPTR *bool `json:"auto_ptr,omitempty"`
+	// Fill (create only, reverse zones) adds a PTR record for every
+	// address of the view's A and AAAA records in the zone's range.
+	Fill bool `json:"fill,omitempty"`
 
 	// Create only: name servers for the apex NS records (default: the
 	// configured default name servers), additional records, and a zone to
@@ -237,6 +260,11 @@ type ViewInput struct {
 	// Exposure is "auto" (or ""), "public" or "private" (docs/exposure.md).
 	Exposure     *string                  `json:"exposure,omitempty"`
 	Acknowledged *[]model.Acknowledgement `json:"acknowledged,omitempty"`
+	// ReverseSuggestions turns the reverse zone suggestions for the
+	// view's addresses on or off (docs/reverse.md).
+	ReverseSuggestions *bool `json:"reverse_suggestions,omitempty"`
+	// DismissedReverse are the networks whose suggestion was dismissed.
+	DismissedReverse *[]string `json:"dismissed_reverse,omitempty"`
 }
 
 // ReorderInput sets the order of views.
@@ -283,6 +311,9 @@ type SettingsInput struct {
 	// Exposure and Acknowledged are the server's (docs/exposure.md).
 	Exposure     *string                  `json:"exposure,omitempty"`
 	Acknowledged *[]model.Acknowledgement `json:"acknowledged,omitempty"`
+	// DismissedReverse are dismissed reverse zone suggestions (without
+	// views).
+	DismissedReverse *[]string `json:"dismissed_reverse,omitempty"`
 }
 
 // DeleteInput carries options for delete operations.

internal/engine/linked_test.go

@@ -341,3 +341,48 @@ func TestCompareZones(t *testing.T) {
 		t.Errorf("sharing the shared version: external %q", v)
 	}
 }
+
+func TestCompareReport(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("example.com"), View: model.Ptr("external"), LinkWith: "internal"}))
+	env.submit(env.admin,
+		NewRequest(OpRRSetReplace, 0, RRSetInput{Zone: "example.com", View: "external", Name: "www", Type: "A", Data: []string{"203.0.113.10"}, Local: model.Ptr(true)}),
+		NewRequest(OpRecordCreate, 0, RecordInput{Zone: "example.com", View: "internal", Name: model.Ptr("nas"), Type: model.Ptr("A"), Data: model.Ptr("10.0.0.20"), Local: model.Ptr(true)}),
+		NewRequest(OpRecordCreate, 0, RecordInput{Zone: "example.com", View: "internal", Name: model.Ptr("printer"), Type: model.Ptr("A"), Data: model.Ptr("10.0.0.30"), Local: model.Ptr(true)}),
+		NewRequest(OpRecordCreate, 0, RecordInput{Zone: "example.com", View: "external", Name: model.Ptr("shop"), Type: model.Ptr("CNAME"), Data: model.Ptr("shops.example.net."), Local: model.Ptr(true)}))
+	st := env.state()
+	zones := []*model.Zone{st.FindZone("example.com.", st.ViewByName("internal").ID), st.FindZone("example.com.", st.ViewByName("external").ID)}
+
+	rep := Compare(st, zones, CompareFilter{})
+	if rep.Base != "internal" || !rep.Linked || !slices.Equal(rep.Views, []string{"internal", "external"}) {
+		t.Errorf("report %+v", rep)
+	}
+	if s := rep.Summary[0]; s.View != "external" || s.Different != 1 || s.OnlyBase != 2 || s.OnlyOther != 1 || s.Same != 2 {
+		t.Errorf("summary %+v", s)
+	}
+	if len(rep.Different) != 1 || rep.Different[0].Name != "www" {
+		t.Errorf("different %+v", rep.Different)
+	}
+	var only []string
+	for _, o := range rep.Only {
+		var names []string
+		for _, r := range o.Rows {
+			names = append(names, r.Name)
+		}
+		only = append(only, strings.Join(o.Views, "+")+": "+strings.Join(names, ","))
+	}
+	want(t, "only", only, "internal: nas,printer", "external: shop")
+	if rep.Same != 2 || rep.SameRows != nil {
+		t.Errorf("same %d, rows %v", rep.Same, rep.SameRows)
+	}
+
+	// One name: just its rows, the same ones included.
+	rep = Compare(st, zones, CompareFilter{Name: "www"})
+	if len(rep.Different) != 1 || len(rep.Only) != 0 || len(rep.SameRows) != 0 {
+		t.Errorf("www: %+v", rep)
+	}
+	rep = Compare(st, zones, CompareFilter{Name: "mail.example.com.", Type: "A"})
+	if len(rep.SameRows) != 1 || rep.SameRows[0].Name != "mail" || len(rep.Different)+len(rep.Only) != 0 {
+		t.Errorf("mail A: %+v", rep)
+	}
+}

internal/engine/ops.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/netip"
+	"slices"
 	"strings"
 	"time"
 
@@ -268,6 +269,9 @@ func setZoneFields(st *model.State, z *model.Zone, in *ZoneInput, creating bool)
 	if in.LinkGroup != nil {
 		z.LinkGroup = *in.LinkGroup
 	}
+	if in.AutoPTR != nil {
+		z.AutoPTR = *in.AutoPTR
+	}
 	return nil
 }
 
@@ -805,6 +809,12 @@ func setViewFields(v *model.View, in *ViewInput) error {
 	if in.Acknowledged != nil {
 		v.Acknowledged = cleanAcks(*in.Acknowledged)
 	}
+	if in.ReverseSuggestions != nil {
+		v.ReverseSuggestionsOff = !*in.ReverseSuggestions
+	}
+	if in.DismissedReverse != nil {
+		v.DismissedReverse = slices.Clone(*in.DismissedReverse)
+	}
 	return nil
 }
 
@@ -1401,6 +1411,9 @@ func applySettings(st *model.State, op model.Op, c *applyCtx) error {
 	if in.Acknowledged != nil {
 		s.Acknowledged = cleanAcks(*in.Acknowledged)
 	}
+	if in.DismissedReverse != nil {
+		s.DismissedReverse = slices.Clone(*in.DismissedReverse)
+	}
 	s.Version++
 	return nil
 }

internal/engine/reverse.go

@@ -0,0 +1,549 @@
+package engine
+
+import (
+	"fmt"
+	"net/netip"
+	"slices"
+	"strings"
+
+	"jarl/internal/dnsname"
+	"jarl/internal/model"
+	"jarl/internal/rr"
+	"jarl/internal/validate"
+)
+
+// Reverse zones made easy (docs/reverse.md): filling a reverse zone from
+// the A and AAAA records of its view, choosing its view, and suggesting
+// the reverse zones a view lacks.
+
+// addrUse is an address a forward record gives a name.
+type addrUse struct {
+	addr netip.Addr
+	name string // the owner name, absolute
+	apex bool
+	view string // another view's record (fillAddresses), else ""
+}
+
+// forwardAddresses returns the addresses of the enabled A and AAAA
+// records of a view's primary forward zones (wildcards aside: a PTR record
+// can't name them).
+func forwardAddresses(st *model.State, viewID int64) []addrUse {
+	var out []addrUse
+	for _, z := range st.ZonesInView(viewID) {
+		if z.Type != model.ZonePrimary || z.Disabled || dnsname.IsReverse(z.Name) {
+			continue
+		}
+		for _, r := range st.ZoneRecords(z.ID) {
+			if r.Disabled || (r.Type != "A" && r.Type != "AAAA") || strings.HasPrefix(r.Name, "*.") {
+				continue
+			}
+			a, err := netip.ParseAddr(r.Data)
+			if err != nil {
+				continue
+			}
+			out = append(out, addrUse{addr: a.Unmap(), name: r.Name, apex: r.Name == z.Name})
+		}
+	}
+	return out
+}
+
+// fillAddresses returns a view's addresses (forwardAddresses), then those
+// of the other views' records that none of its own records use, marked
+// with their view: a reverse zone in the internal view can name a host
+// only the external view has a record for.
+func fillAddresses(st *model.State, viewID int64) []addrUse {
+	out := forwardAddresses(st, viewID)
+	if len(st.Views) == 0 {
+		return out
+	}
+	own := map[netip.Addr]bool{}
+	for _, u := range out {
+		own[u.addr] = true
+	}
+	for _, v := range st.OrderedViews() {
+		if v.ID == viewID {
+			continue
+		}
+		for _, u := range forwardAddresses(st, v.ID) {
+			if !own[u.addr] {
+				u.view = v.Name
+				out = append(out, u)
+			}
+		}
+	}
+	return out
+}
+
+// PTRFill is a PTR record filling a reverse zone would add.
+type PTRFill struct {
+	Address string   `json:"address"`
+	Name    string   `json:"name"`             // the PTR owner name
+	Target  string   `json:"target"`           // the host name it gives
+	Others  []string `json:"others,omitempty"` // other names with this address
+	// From is the view whose record names the host, when the zone's own
+	// view has none for the address.
+	From string `json:"from,omitempty"`
+}
+
+// PTRFills returns the PTR records a reverse zone named zoneName in a view
+// lacks for the addresses of the view's A and AAAA records: one per
+// address, naming its mail or name server host when it is one, otherwise
+// a host rather than the domain itself, then the shortest name. An
+// address no record of the view uses is named from another view's
+// records (fillAddresses), marked From. existing are the zone's records
+// (none for a new zone).
+func PTRFills(st *model.State, viewID int64, zoneName string, existing []*model.Record) []PTRFill {
+	prefix, ok := dnsname.PrefixFromReverse(zoneName)
+	if !ok {
+		return nil
+	}
+	has := map[string]bool{}
+	for _, r := range existing {
+		if r.Type == "PTR" {
+			has[r.Name] = true
+		}
+	}
+	servers := serverNames(st, viewID)
+	byAddr := map[netip.Addr][]addrUse{}
+	var order []netip.Addr
+	for _, u := range fillAddresses(st, viewID) {
+		if !prefix.Contains(u.addr) {
+			continue
+		}
+		if _, seen := byAddr[u.addr]; !seen {
+			order = append(order, u.addr)
+		}
+		if !slices.ContainsFunc(byAddr[u.addr], func(o addrUse) bool { return o.name == u.name }) {
+			byAddr[u.addr] = append(byAddr[u.addr], u)
+		}
+	}
+	slices.SortFunc(order, func(a, b netip.Addr) int { return a.Compare(b) })
+	var out []PTRFill
+	for _, a := range order {
+		owner := dnsname.ReverseName(a)
+		if has[owner] {
+			continue
+		}
+		uses := byAddr[a]
+		slices.SortStableFunc(uses, func(x, y addrUse) int {
+			rank := func(u addrUse) int {
+				switch {
+				case servers[u.name]:
+					return 0
+				case !u.apex:
+					return 1
+				}
+				return 2
+			}
+			if d := rank(x) - rank(y); d != 0 {
+				return d
+			}
+			if d := strings.Count(x.name, ".") - strings.Count(y.name, "."); d != 0 {
+				return d
+			}
+			return strings.Compare(x.name, y.name)
+		})
+		f := PTRFill{Address: a.String(), Name: owner, Target: uses[0].name, From: uses[0].view}
+		for _, u := range uses[1:] {
+			if u.name != f.Target {
+				f.Others = append(f.Others, u.name)
+			}
+		}
+		out = append(out, f)
+	}
+	return out
+}
+
+// serverNames are the hosts the view's MX and NS records name.
+func serverNames(st *model.State, viewID int64) map[string]bool {
+	out := map[string]bool{}
+	for _, z := range st.ZonesInView(viewID) {
+		if z.Type != model.ZonePrimary {
+			continue
+		}
+		for _, r := range st.ZoneRecords(z.ID) {
+			switch r.Type {
+			case "MX":
+				if f := strings.Fields(r.Data); len(f) == 2 {
+					out[strings.ToLower(f[1])] = true
+				}
+			case "NS":
+				out[strings.ToLower(r.Data)] = true
+			}
+		}
+	}
+	return out
+}
+
+func fillWarnings(fills []PTRFill) []string {
+	var out []string
+	for _, f := range fills {
+		if f.From != "" {
+			out = append(out, fmt.Sprintf("%s: only view %s has a record for it, so its PTR record gives %s from there", f.Address, f.From, dnsname.Display(f.Target)))
+		}
+		if len(f.Others) > 0 {
+			out = append(out, fmt.Sprintf("%s has several names: its PTR record gives %s (not %s); change it if you prefer another", f.Address, dnsname.Display(f.Target), strings.Join(displayAll(f.Others), ", ")))
+		}
+	}
+	return out
+}
+
+func displayAll(names []string) []string {
+	out := make([]string, len(names))
+	for i, n := range names {
+		out[i] = dnsname.Display(n)
+	}
+	return out
+}
+
+// zoneFillPTR expands zone.fill_ptr: the PTR records a reverse zone lacks.
+func (x *expander) zoneFillPTR(req Request) ([]model.Op, error) {
+	var in LinkInput
+	if err := decode(req.Data, &in); err != nil {
+		return nil, err
+	}
+	id := in.ZoneID
+	if id == 0 {
+		id = req.ID
+	}
+	z := x.st.Zones[id]
+	if z == nil {
+		return nil, errf(KindNotFound, "zone %d does not exist", id)
+	}
+	if z.Type != model.ZonePrimary {
+		return nil, errf(KindBadRequest, "zone %s isn't a primary zone", zoneDesc(x.st, z))
+	}
+	if _, ok := dnsname.PrefixFromReverse(z.Name); !ok {
+		return nil, errf(KindBadRequest, "zone %s isn't a reverse zone of whole octets or nibbles (like 10.0.10.in-addr.arpa)", zoneDesc(x.st, z))
+	}
+	fills := PTRFills(x.st, z.ViewID, z.Name, x.st.ZoneRecords(z.ID))
+	if len(fills) == 0 {
+		return nil, errf(KindBadRequest, "nothing to add: every address of %s's A and AAAA records in %s has a PTR record", viewOrServer(x.st, z.ViewID), zoneDesc(x.st, z))
+	}
+	x.warnings = append(x.warnings, fillWarnings(fills)...)
+	ids, err := x.ids(len(fills))
+	if err != nil {
+		return nil, err
+	}
+	var ops []model.Op
+	for i, f := range fills {
+		ri := RecordInput{ZoneID: z.ID, Name: model.Ptr(f.Name), Type: model.Ptr("PTR"), Data: model.Ptr(f.Target)}
+		if z.LinkGroup != 0 {
+			ri.SharedID = model.Ptr(ids[i])
+		}
+		ops = append(ops, newOp(OpRecordCreate, ids[i], 0, ri, fmt.Sprintf("add %s IN PTR %s", f.Name, f.Target)))
+	}
+	return ops, nil
+}
+
+func viewOrServer(st *model.State, viewID int64) string {
+	if v := st.Views[viewID]; v != nil {
+		return "view " + v.Name
+	}
+	return "the server"
+}
+
+// publicViews returns which views the internet reaches.
+func (x *expander) publicViews() map[int64]bool {
+	out := map[int64]bool{}
+	if x.exposures == nil {
+		return out
+	}
+	for _, e := range x.exposures(x.st) {
+		out[e.ViewID] = e.Public
+	}
+	return out
+}
+
+// reverseViewFor chooses the view of a new reverse zone given without one:
+// the private view whose records use addresses in its range, or the only
+// private view; views with reverse suggestions off don't count. nil with
+// no error leaves the choice to the usual rules.
+func reverseViewFor(st *model.State, public map[int64]bool, zoneName string) (*model.View, error) {
+	prefix, ok := dnsname.PrefixFromReverse(zoneName)
+	if !ok || len(st.Views) == 0 {
+		return nil, nil
+	}
+	var private, using []*model.View
+	for _, v := range st.OrderedViews() {
+		if public[v.ID] || v.ReverseSuggestionsOff {
+			continue
+		}
+		private = append(private, v)
+		if slices.ContainsFunc(forwardAddresses(st, v.ID), func(u addrUse) bool { return prefix.Contains(u.addr) }) {
+			using = append(using, v)
+		}
+	}
+	switch {
+	case len(using) == 1:
+		return using[0], nil
+	case len(using) > 1:
+		var names []string
+		for _, v := range using {
+			names = append(names, v.Name)
+		}
+		return nil, errf(KindBadRequest, "views %s all have addresses in %s: give the view (or create the zone in each)", strings.Join(names, " and "), prefix)
+	case len(private) == 1:
+		return private[0], nil
+	}
+	return nil, nil
+}
+
+// ReverseSuggestion is a reverse zone a view lacks for addresses its
+// records use.
+type ReverseSuggestion struct {
+	ViewID int64  `json:"view_id"`
+	View   string `json:"view,omitempty"`
+	Prefix string `json:"prefix"`
+	Zone   string `json:"zone"`
+	// Group is "yours" for networks that are yours for sure (private
+	// ranges, IPv6 prefixes this server has an address in), "public" for
+	// a public address that may be someone else's (a web host's).
+	Group string `json:"group"`
+	// Hidden says why the suggestion isn't made unasked (with All only):
+	// "public view", "suggestions off" or "dismissed".
+	Hidden  string   `json:"hidden,omitempty"`
+	Why     string   `json:"why"`
+	Fill    int      `json:"fill"`    // PTR records creating it with fill adds
+	Samples []string `json:"samples"` // a few of them, "address name"
+}
+
+// Suggestion groups.
+const (
+	SuggestYours  = "yours"
+	SuggestPublic = "public"
+)
+
+// ReverseSuggestions returns the reverse zones the private views (or the
+// server, without views) lack for their A and AAAA records' addresses:
+//
+//   - yours: the /24 of a private IPv4 address, the /48 of a ULA or of a
+//     public IPv6 prefix this server has an address in (local);
+//   - public: a /32 (or /128) for any other public address. It may be a
+//     web host's; the rest of its /24 surely belongs to others, and a
+//     zone for it here would hide their names from your clients.
+//
+// Public views, views with suggestions turned off and dismissed networks
+// get none: the internet asks the addresses' owners.
+func ReverseSuggestions(st *model.State, exposures []validate.Exposure, local []netip.Addr) []ReverseSuggestion {
+	return ReverseCandidates(st, exposures, local, ReverseOptions{})
+}
+
+// ReverseOptions widen or narrow ReverseCandidates.
+type ReverseOptions struct {
+	// All includes what isn't suggested unasked, marked Hidden: public
+	// views, views with suggestions off, dismissed networks.
+	All bool
+	// View narrows it to one view (by name; "" all). With All, the view
+	// also gets the addresses only other views' records use, marked
+	// Hidden "records in VIEW": a reverse zone there can name them.
+	View string
+}
+
+// ReverseCandidates is ReverseSuggestions with options: with All, every
+// network the views' records use that no reverse zone in their view
+// covers, for creating one by hand where suggestions are off.
+func ReverseCandidates(st *model.State, exposures []validate.Exposure, local []netip.Addr, opt ReverseOptions) []ReverseSuggestion {
+	public := map[int64]bool{}
+	for _, e := range exposures {
+		public[e.ViewID] = e.Public
+	}
+	type scope struct {
+		id        int64
+		dismissed []string
+		hidden    string
+	}
+	var scopes []scope
+	if len(st.Views) > 0 {
+		for _, v := range st.OrderedViews() {
+			if opt.View != "" && !strings.EqualFold(v.Name, opt.View) {
+				continue
+			}
+			hidden := ""
+			switch {
+			case public[v.ID]:
+				hidden = "public view"
+			case v.ReverseSuggestionsOff:
+				hidden = "suggestions off"
+			}
+			if hidden == "" || opt.All {
+				scopes = append(scopes, scope{v.ID, v.DismissedReverse, hidden})
+			}
+		}
+	} else if !public[0] || opt.All {
+		hidden := ""
+		if public[0] {
+			hidden = "public server"
+		}
+		scopes = append(scopes, scope{0, st.Settings.DismissedReverse, hidden})
+	}
+	out := []ReverseSuggestion{}
+	for _, sc := range scopes {
+		seen := map[netip.Prefix]bool{}
+		addrs := forwardAddresses(st, sc.id)
+		if opt.All && opt.View != "" {
+			addrs = fillAddresses(st, sc.id)
+		}
+		for _, u := range addrs {
+			a := u.addr
+			if a.IsLoopback() || a.IsLinkLocalUnicast() || a.IsUnspecified() || a.IsMulticast() {
+				continue
+			}
+			if rz, _ := reverseZoneFor(st, sc.id, a); rz != nil {
+				continue
+			}
+			p, group, why := suggestedPrefix(a, local)
+			hidden := sc.hidden
+			if hidden == "" && u.view != "" {
+				hidden = "records in " + u.view
+			}
+			if seen[p] {
+				continue
+			}
+			if slices.Contains(sc.dismissed, p.String()) {
+				if !opt.All {
+					continue
+				}
+				if hidden == "" {
+					hidden = "dismissed"
+				}
+			}
+			seen[p] = true
+			name, err := dnsname.ReverseZone(p)
+			if err != nil {
+				continue
+			}
+			s := ReverseSuggestion{ViewID: sc.id, View: viewName(st, sc.id), Prefix: p.String(), Zone: strings.TrimSuffix(name, "."), Group: group, Hidden: hidden, Why: why, Samples: []string{}}
+			fills := PTRFills(st, sc.id, name, nil)
+			s.Fill = len(fills)
+			for i, f := range fills {
+				if i == 3 {
+					break
+				}
+				s.Samples = append(s.Samples, f.Address+" "+dnsname.Display(f.Target))
+			}
+			out = append(out, s)
+		}
+	}
+	slices.SortStableFunc(out, func(a, b ReverseSuggestion) int {
+		if a.Group != b.Group {
+			return strings.Compare(b.Group, a.Group) // yours first
+		}
+		if a.View != b.View {
+			return strings.Compare(a.View, b.View)
+		}
+		return netip.MustParsePrefix(a.Prefix).Addr().Compare(netip.MustParsePrefix(b.Prefix).Addr())
+	})
+	return out
+}
+
+// suggestedPrefix returns the reverse zone network for an address, its
+// group and why.
+func suggestedPrefix(a netip.Addr, local []netip.Addr) (netip.Prefix, string, string) {
+	switch {
+	case a.Is4() && (a.IsPrivate() || cgnat.Contains(a)):
+		return netip.PrefixFrom(a, 24).Masked(), SuggestYours, "private network"
+	case a.Is4():
+		return netip.PrefixFrom(a, 32), SuggestPublic, "a public address: create it only if it is yours (not a web host's); the rest of its /24 belongs to others"
+	case a.IsPrivate():
+		return netip.PrefixFrom(a, 48).Masked(), SuggestYours, "your ULA /48 (one zone for all its subnets)"
+	}
+	p := netip.PrefixFrom(a, 48).Masked()
+	if slices.ContainsFunc(local, func(l netip.Addr) bool { return p.Contains(l.Unmap()) }) {
+		return p, SuggestYours, "your IPv6 /48 (this server has an address in it): one zone for all its subnets"
+	}
+	return netip.PrefixFrom(a, 128), SuggestPublic, "a public address outside this server's networks: create it only if it is yours"
+}
+
+// ReverseSuggestions lists the reverse zones the views lack (opt.All:
+// also where suggestions aren't made unasked).
+func (e *Engine) ReverseSuggestions(st *model.State, opt ReverseOptions) []ReverseSuggestion {
+	var local []netip.Addr
+	if e.cfg.LocalAddrs != nil {
+		local = e.cfg.LocalAddrs()
+	}
+	return ReverseCandidates(st, e.Exposures(st), local, opt)
+}
+
+// reverseDismiss expands reverse.dismiss and reverse.undismiss.
+func (x *expander) reverseDismiss(req Request, dismiss bool) ([]model.Op, error) {
+	var in DismissInput
+	if err := decode(req.Data, &in); err != nil {
+		return nil, err
+	}
+	raw := in.Prefixes
+	if in.Prefix != "" {
+		raw = append(raw, in.Prefix)
+	}
+	if len(raw) == 0 {
+		return nil, errf(KindBadRequest, "give the network (prefix) of the suggestion")
+	}
+	var prefixes []string
+	for _, r := range raw {
+		p, err := netip.ParsePrefix(strings.TrimSpace(r))
+		if err != nil {
+			return nil, errf(KindBadRequest, "prefix: %v", err)
+		}
+		if s := p.Masked().String(); !slices.Contains(prefixes, s) {
+			prefixes = append(prefixes, s)
+		}
+	}
+	var v *model.View
+	switch {
+	case in.ViewID != 0:
+		v = x.st.Views[in.ViewID]
+	case in.View != "":
+		v = x.st.ViewByName(in.View)
+	}
+	if (in.ViewID != 0 || in.View != "") && v == nil {
+		return nil, errf(KindNotFound, "no view %s", firstNonEmptyStr(in.View, fmt.Sprint(in.ViewID)))
+	}
+	if v == nil && len(x.st.Views) > 0 {
+		return nil, errf(KindBadRequest, "give the view of the suggestion")
+	}
+	list, where := x.st.Settings.DismissedReverse, "the server"
+	if v != nil {
+		list, where = v.DismissedReverse, "view "+v.Name
+	}
+	out := slices.DeleteFunc(slices.Clone(list), func(s string) bool { return slices.Contains(prefixes, s) })
+	what := prefixes[0]
+	if len(prefixes) > 1 {
+		what = fmt.Sprintf("%d networks (%s, …)", len(prefixes), prefixes[0])
+	}
+	summary := "dismiss the reverse zone suggestion for " + what + " in " + where
+	if dismiss {
+		out = append(out, prefixes...)
+		slices.Sort(out)
+	} else {
+		if len(out) == len(list) {
+			return nil, errf(KindConflict, "%s isn't dismissed in %s", what, where)
+		}
+		summary = "suggest a reverse zone for " + what + " in " + where + " again"
+	}
+	if out == nil {
+		out = []string{}
+	}
+	if v != nil {
+		return []model.Op{newOp(OpViewUpdate, v.ID, v.Version, ViewInput{DismissedReverse: &out}, summary)}, nil
+	}
+	return []model.Op{newOp(OpSettingsUpdate, 0, 0, SettingsInput{DismissedReverse: &out}, summary)}, nil
+}
+
+var cgnat = netip.MustParsePrefix("100.64.0.0/10")
+
+// autoPTR reports whether a record's PTR is kept in step by its zone's
+// auto_ptr setting.
+func autoPTR(z *model.Zone, owner string, p *rr.Parsed) bool {
+	if z == nil || !z.AutoPTR || strings.HasPrefix(owner, "*.") {
+		return false
+	}
+	_, ok := addrOf(p)
+	return ok
+}
+
+func viewName(st *model.State, id int64) string {
+	if v := st.Views[id]; v != nil {
+		return v.Name
+	}
+	return ""
+}

internal/engine/reverse_test.go

@@ -0,0 +1,305 @@
+package engine
+
+import (
+	"net/netip"
+	"slices"
+	"strings"
+	"testing"
+
+	"jarl/internal/model"
+)
+
+// ptrs returns a reverse zone's PTR records in a view as "owner target",
+// with " disabled" when so.
+func (env *testEnv) ptrs(view, zone string) []string {
+	env.t.Helper()
+	s := env.state()
+	z := s.FindZone(zone, s.ViewByName(view).ID)
+	if z == nil {
+		env.t.Fatalf("no zone %s in %s", zone, view)
+	}
+	var out []string
+	for _, r := range s.ZoneRecords(z.ID) {
+		if r.Type == "PTR" {
+			d := r.Name + " " + r.Data
+			if r.Disabled {
+				d += " disabled"
+			}
+			out = append(out, d)
+		}
+	}
+	return out
+}
+
+func TestReverseFillAndSuggest(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin,
+		recIn("internal", "@", "A", "192.0.2.25"),
+		recIn("internal", "nas", "A", "10.0.10.20"),
+		recIn("internal", "files", "A", "10.0.10.20"),
+		recIn("internal", "nas", "AAAA", "fdab:abab:abab:10::20"),
+		recIn("internal", "*.dev", "A", "10.0.10.99"),
+		recIn("internal", "lo", "A", "127.0.0.1"))
+
+	sugg := ReverseSuggestions(env.state(), env.e.Exposures(env.state()), nil)
+	var got []string
+	for _, s := range sugg {
+		got = append(got, s.Group+" "+s.View+" "+s.Prefix+" "+s.Zone)
+	}
+	want(t, "suggestions", got,
+		"yours internal 10.0.10.0/24 10.0.10.in-addr.arpa",
+		"yours internal fdab:abab:abab::/48 b.a.b.a.b.a.b.a.b.a.d.f.ip6.arpa",
+		"public internal 192.0.2.10/32 10.2.0.192.in-addr.arpa",
+		"public internal 192.0.2.25/32 25.2.0.192.in-addr.arpa")
+	if sugg[0].Fill != 1 || sugg[0].Samples[0] != "10.0.10.20 files.example.com" {
+		t.Errorf("10.0.10.0/24: %+v", sugg[0])
+	}
+
+	// No view given: the private view whose records use the addresses.
+	res := env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("10.0.10.0/24"), Fill: true}))
+	want(t, "10.0.10/24", env.ptrs("internal", "10.0.10.in-addr.arpa."), "20.10.0.10.in-addr.arpa. files.example.com.")
+	if !slices.ContainsFunc(res.Warnings, func(w string) bool { return strings.Contains(w, "10.0.10.20 has several names") }) {
+		t.Errorf("warnings %q", res.Warnings)
+	}
+	// The mail server's name beats the domain's own.
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("192.0.2.25/32"), Fill: true}))
+	want(t, "192.0.2.25", env.ptrs("internal", "25.2.0.192.in-addr.arpa."), "25.2.0.192.in-addr.arpa. mail.example.com.")
+
+	// Filling an existing zone; then there is nothing left to add.
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("fdab:abab:abab::/48")}))
+	st := env.state()
+	z6 := st.FindZone("b.a.b.a.b.a.b.a.b.a.d.f.ip6.arpa.", st.ViewByName("internal").ID)
+	env.submit(env.admin, NewRequest(OpZoneFillPTR, z6.ID, LinkInput{}))
+	if p := env.ptrs("internal", z6.Name); len(p) != 1 || !strings.HasSuffix(p[0], " nas.example.com.") {
+		t.Errorf("ip6 fill: %q", p)
+	}
+	if e := env.submitErr(env.admin, NewRequest(OpZoneFillPTR, z6.ID, LinkInput{})); !strings.Contains(e.Message, "nothing to add") {
+		t.Errorf("second fill: %v", e)
+	}
+
+	got = got[:0]
+	for _, s := range ReverseSuggestions(env.state(), env.e.Exposures(env.state()), nil) {
+		got = append(got, s.Prefix)
+	}
+	want(t, "suggestions left", got, "192.0.2.10/32")
+
+	// Addresses that two private views use: the view must be given.
+	env.submit(env.admin, NewRequest(OpViewCreate, 0, ViewInput{Name: model.Ptr("lab"), MatchClients: &[]string{"172.16.0.0/12"}}))
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("lab.test"), View: model.Ptr("lab")}),
+		NewRequest(OpRecordCreate, 0, RecordInput{Zone: "lab.test", View: "lab", Name: model.Ptr("x"), Type: model.Ptr("A"), Data: model.Ptr("192.0.2.10")}))
+	if e := env.submitErr(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("192.0.2.10/32")})); !strings.Contains(e.Message, "views internal and lab all have addresses") {
+		t.Errorf("two views: %v", e)
+	}
+}
+
+func TestAutoPTR(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("10.0.10.0/24"), View: model.Ptr("internal")}))
+	st := env.state()
+	zid := st.FindZone("example.com.", st.ViewByName("internal").ID).ID
+	env.submit(env.admin, NewRequest(OpZoneUpdate, zid, ZoneInput{AutoPTR: model.Ptr(true)}))
+	rz := "10.0.10.in-addr.arpa."
+
+	res := env.submit(env.admin, recIn("internal", "host", "A", "10.0.10.30"), recIn("internal", "pub", "A", "203.0.113.5"))
+	want(t, "added", env.ptrs("internal", rz), "30.10.0.10.in-addr.arpa. host.example.com.")
+	if len(res.Warnings) > 0 {
+		t.Errorf("no reverse zone for 203.0.113.5 isn't worth a warning: %q", res.Warnings)
+	}
+	// A second name for the address: its PTR stays.
+	res = env.submit(env.admin, recIn("internal", "alias", "A", "10.0.10.30"))
+	want(t, "second name", env.ptrs("internal", rz), "30.10.0.10.in-addr.arpa. host.example.com.")
+	if len(res.Warnings) > 0 {
+		t.Errorf("warnings %q", res.Warnings)
+	}
+	env.submit(env.admin, NewRequest(OpRecordDelete, env.recordID("internal", "alias", "A"), nil))
+
+	// Moved, disabled, enabled, deleted.
+	env.submit(env.admin, NewRequest(OpRecordUpdate, env.recordID("internal", "host", "A"), RecordInput{Data: model.Ptr("10.0.10.31")}))
+	want(t, "moved", env.ptrs("internal", rz), "31.10.0.10.in-addr.arpa. host.example.com.")
+	env.submit(env.admin, NewRequest(OpRecordUpdate, env.recordID("internal", "host", "A"), RecordInput{Disabled: model.Ptr(true)}))
+	want(t, "disabled", env.ptrs("internal", rz), "31.10.0.10.in-addr.arpa. host.example.com. disabled")
+	env.submit(env.admin, NewRequest(OpRecordUpdate, env.recordID("internal", "host", "A"), RecordInput{Disabled: model.Ptr(false)}))
+	want(t, "enabled", env.ptrs("internal", rz), "31.10.0.10.in-addr.arpa. host.example.com.")
+	env.submit(env.admin, NewRequest(OpRecordDelete, env.recordID("internal", "host", "A"), nil))
+	want(t, "deleted", env.ptrs("internal", rz))
+
+	// A whole set replaced.
+	env.submit(env.admin, NewRequest(OpRRSetReplace, 0, RRSetInput{Zone: "example.com", View: "internal", Name: "multi", Type: "A", Data: []string{"10.0.10.40", "10.0.10.41"}}))
+	want(t, "set", env.ptrs("internal", rz), "40.10.0.10.in-addr.arpa. multi.example.com.", "41.10.0.10.in-addr.arpa. multi.example.com.")
+	env.submit(env.admin, NewRequest(OpRRSetReplace, 0, RRSetInput{Zone: "example.com", View: "internal", Name: "multi", Type: "A", Data: []string{"10.0.10.41"}}))
+	want(t, "set shrunk", env.ptrs("internal", rz), "41.10.0.10.in-addr.arpa. multi.example.com.")
+	// Deleting by name and type.
+	env.submit(env.admin, NewRequest(OpRecordDelete, 0, RecordInput{Zone: "example.com", View: "internal", Name: model.Ptr("multi"), Type: model.Ptr("A")}))
+	want(t, "deleted by match", env.ptrs("internal", rz))
+
+	// Off again: records come and go alone.
+	env.submit(env.admin, NewRequest(OpZoneUpdate, zid, ZoneInput{AutoPTR: model.Ptr(false)}))
+	env.submit(env.admin, recIn("internal", "quiet", "A", "10.0.10.50"))
+	want(t, "off", env.ptrs("internal", rz))
+}
+
+func suggested(env *testEnv, local ...netip.Addr) []string {
+	var out []string
+	for _, s := range ReverseSuggestions(env.state(), env.e.Exposures(env.state()), local) {
+		out = append(out, s.Group+" "+s.View+" "+s.Prefix)
+	}
+	return out
+}
+
+// Public IPv6: the /48 only when this server has an address in it, else
+// the address alone, as a public suggestion. Dismissed networks and views
+// with suggestions off get none.
+func TestReverseSuggestionGroups(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin,
+		recIn("internal", "home", "AAAA", "2a02:8013:7f3d:10::5"),
+		recIn("internal", "gh", "AAAA", "2606:50c0:8000::153"))
+	want(t, "no local addresses", suggested(env),
+		"public internal 192.0.2.10/32", "public internal 192.0.2.25/32",
+		"public internal 2606:50c0:8000::153/128", "public internal 2a02:8013:7f3d:10::5/128")
+	want(t, "this server is in 2a02:8013:7f3d::/48", suggested(env, netip.MustParseAddr("2a02:8013:7f3d:10:1266:6aff:fef9:f5b1")),
+		"yours internal 2a02:8013:7f3d::/48",
+		"public internal 192.0.2.10/32", "public internal 192.0.2.25/32", "public internal 2606:50c0:8000::153/128")
+
+	env.submit(env.admin, NewRequest(OpReverseDismiss, 0, DismissInput{View: "internal", Prefix: "2606:50c0:8000::153/128"}))
+	if got := suggested(env); slices.Contains(got, "public internal 2606:50c0:8000::153/128") {
+		t.Errorf("dismissed still suggested: %q", got)
+	}
+	if e := env.submitErr(env.admin, NewRequest(OpReverseUndismiss, 0, DismissInput{View: "internal", Prefix: "192.0.2.10/32"})); e.Kind != KindConflict {
+		t.Errorf("undismiss of one not dismissed: %v", e)
+	}
+	env.submit(env.admin, NewRequest(OpReverseUndismiss, 0, DismissInput{View: "internal", Prefix: "2606:50c0:8000::153/128"}))
+	// Several at once.
+	env.submit(env.admin, NewRequest(OpReverseDismiss, 0, DismissInput{View: "internal", Prefixes: []string{"192.0.2.10/32", "192.0.2.25/32"}}))
+	if got := suggested(env); slices.ContainsFunc(got, func(s string) bool { return strings.Contains(s, "192.0.2.") }) {
+		t.Errorf("dismissed together, still suggested: %q", got)
+	}
+	env.submit(env.admin, NewRequest(OpReverseUndismiss, 0, DismissInput{View: "internal", Prefixes: []string{"192.0.2.10/32", "192.0.2.25/32"}}))
+	if got := suggested(env); !slices.Contains(got, "public internal 2606:50c0:8000::153/128") {
+		t.Errorf("undismissed not suggested: %q", got)
+	}
+
+	// A second private view using the same address (a VPS's view): with
+	// its suggestions off it gets none, and doesn't count when choosing
+	// the view of a new reverse zone.
+	env.submit(env.admin, NewRequest(OpViewCreate, 0, ViewInput{Name: model.Ptr("vps"), MatchClients: &[]string{"198.51.100.7"}}))
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("example.com"), View: model.Ptr("vps"), LinkWith: "internal"}))
+	if got := suggested(env); !slices.Contains(got, "public vps 192.0.2.25/32") {
+		t.Errorf("vps view: %q", got)
+	}
+	if e := env.submitErr(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("192.0.2.25/32")})); !strings.Contains(e.Message, "views internal and vps") {
+		t.Errorf("two views: %v", e)
+	}
+	vps := env.state().ViewByName("vps")
+	env.submit(env.admin, NewRequest(OpViewUpdate, vps.ID, ViewInput{ReverseSuggestions: model.Ptr(false)}))
+	if got := suggested(env); slices.ContainsFunc(got, func(s string) bool { return strings.Contains(s, " vps ") }) {
+		t.Errorf("vps view with suggestions off: %q", got)
+	}
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("192.0.2.25/32"), Fill: true}))
+	want(t, "went to internal", env.ptrs("internal", "25.2.0.192.in-addr.arpa."), "25.2.0.192.in-addr.arpa. mail.example.com.")
+}
+
+// A zone created inside another takes the parent's records under it.
+func TestChildZoneTakesRecords(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("10.0.0.0/8"), View: model.Ptr("internal")}))
+	ptr := func(name, data string) Request {
+		return NewRequest(OpRecordCreate, 0, RecordInput{Zone: "10.in-addr.arpa", View: "internal", Name: &name, Type: model.Ptr("PTR"), Data: &data})
+	}
+	env.submit(env.admin, ptr("20.10.0.10.in-addr.arpa.", "printer.example.com."), ptr("5.20.0.10.in-addr.arpa.", "other.example.com."))
+	env.submit(env.admin, recIn("internal", "nas", "A", "10.0.10.30"))
+	res := env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("10.0.10.0/24"), View: model.Ptr("internal"), Fill: true}))
+	want(t, "/24", env.ptrs("internal", "10.0.10.in-addr.arpa."),
+		"20.10.0.10.in-addr.arpa. printer.example.com.", "30.10.0.10.in-addr.arpa. nas.example.com.")
+	want(t, "/8 keeps the rest", env.ptrs("internal", "10.in-addr.arpa."), "5.20.0.10.in-addr.arpa. other.example.com.")
+	for _, p := range res.Problems {
+		if p.Code == "shadowed_by_zone" {
+			t.Errorf("still hidden records: %v", p)
+		}
+	}
+
+	// A forward child: its delegation and glue stay in the parent.
+	env.submit(env.admin,
+		recIn("internal", "lab", "NS", "ns.lab.example.com."),
+		recIn("internal", "ns.lab", "A", "10.0.30.1"),
+		recIn("internal", "www.lab", "A", "10.0.30.2"))
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("lab.example.com"), View: model.Ptr("internal")}))
+	st := env.state()
+	lab := st.FindZone("lab.example.com.", st.ViewByName("internal").ID)
+	var labRecs []string
+	for _, r := range st.ZoneRecords(lab.ID) {
+		if r.Type != "NS" {
+			labRecs = append(labRecs, r.Name+" "+r.Type)
+		}
+	}
+	want(t, "lab", labRecs, "www.lab.example.com. A")
+	v := env.view("internal") // without NS records
+	if !slices.Contains(v, "ns.lab A 10.0.30.1 L") || slices.ContainsFunc(v, func(s string) bool { return strings.HasPrefix(s, "www.lab ") }) {
+		t.Errorf("parent after: %q", v)
+	}
+	if env.recordID("internal", "lab", "NS") == 0 {
+		t.Error("the delegation left the parent")
+	}
+}
+
+// With All, the networks no suggestion is made for unasked are listed too,
+// marked: views with suggestions off, dismissed ones, public views.
+func TestReverseCandidatesAll(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("example.com"), View: model.Ptr("external"), LinkWith: "internal"}))
+	env.submit(env.admin, NewRequest(OpRRSetReplace, 0, RRSetInput{Zone: "example.com", View: "internal", Name: "nas", Type: "AAAA", Data: []string{"2a02:8013:7f3d:10::5"}, Local: model.Ptr(true)}))
+	env.submit(env.admin, NewRequest(OpReverseDismiss, 0, DismissInput{View: "internal", Prefix: "192.0.2.10/32"}))
+	internal := env.state().ViewByName("internal")
+	env.submit(env.admin, NewRequest(OpViewUpdate, internal.ID, ViewInput{ReverseSuggestions: model.Ptr(false)}))
+	list := func(opt ReverseOptions) []string {
+		var out []string
+		for _, s := range ReverseCandidates(env.state(), env.e.Exposures(env.state()), nil, opt) {
+			out = append(out, s.View+" "+s.Prefix+" "+s.Hidden)
+		}
+		return out
+	}
+	want(t, "unasked", list(ReverseOptions{}))
+	want(t, "internal, all", list(ReverseOptions{All: true, View: "internal"}),
+		"internal 192.0.2.10/32 suggestions off", "internal 192.0.2.25/32 suggestions off", "internal 2a02:8013:7f3d:10::5/128 suggestions off")
+	got := list(ReverseOptions{All: true, View: "external"})
+	want(t, "external, all", got, "external 192.0.2.10/32 public view", "external 192.0.2.25/32 public view", "external 2a02:8013:7f3d:10::5/128 public view")
+
+	env.submit(env.admin, NewRequest(OpViewUpdate, internal.ID, ViewInput{ReverseSuggestions: model.Ptr(true)}))
+	want(t, "dismissed", list(ReverseOptions{All: true, View: "internal"}),
+		"internal 192.0.2.10/32 dismissed", "internal 192.0.2.25/32 ", "internal 2a02:8013:7f3d:10::5/128 ")
+}
+
+// An address only another view has a record for: a reverse zone in the
+// internal view is offered for it, and filled from that view's record.
+func TestReverseFromOtherView(t *testing.T) {
+	env := linkedEnv(t)
+	env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("example.com"), View: model.Ptr("external"), LinkWith: "internal"}))
+	env.submit(env.admin, NewRequest(OpRRSetReplace, 0, RRSetInput{Zone: "example.com", View: "external", Name: "vps", Type: "AAAA", Data: []string{"2600:3c01::f03c:93ff:fe2b:1"}, Local: model.Ptr(true)}))
+	var got []string
+	for _, s := range ReverseCandidates(env.state(), env.e.Exposures(env.state()), nil, ReverseOptions{All: true, View: "internal"}) {
+		got = append(got, s.Prefix+" "+s.Hidden)
+	}
+	if !slices.Contains(got, "2600:3c01::f03c:93ff:fe2b:1/128 records in external") {
+		t.Errorf("internal candidates %q", got)
+	}
+	// Not suggested unasked: the internal view's own records don't use it.
+	for _, s := range ReverseSuggestions(env.state(), env.e.Exposures(env.state()), nil) {
+		if strings.HasPrefix(s.Prefix, "2600:") {
+			t.Errorf("suggested unasked: %+v", s)
+		}
+	}
+	res := env.submit(env.admin, NewRequest(OpZoneCreate, 0, ZoneInput{Name: model.Ptr("2600:3c01::f03c:93ff:fe2b:1/128"), View: model.Ptr("internal"), Fill: true}))
+	st := env.state()
+	var zone string
+	for _, z := range st.ZonesInView(st.ViewByName("internal").ID) {
+		if strings.HasSuffix(z.Name, ".ip6.arpa.") {
+			zone = z.Name
+		}
+	}
+	if p := env.ptrs("internal", zone); len(p) != 1 || !strings.HasSuffix(p[0], " vps.example.com.") {
+		t.Errorf("filled %q", p)
+	}
+	if !slices.ContainsFunc(res.Warnings, func(w string) bool { return strings.Contains(w, "only view external has a record for it") }) {
+		t.Errorf("warnings %q", res.Warnings)
+	}
+}

internal/engine/viewkeys.go

@@ -66,3 +66,9 @@ func (e *Engine) ViewKey(ctx context.Context, st *model.State, z *model.Zone) *n
 	}
 	return &nscheck.Key{Name: render.ViewKeyName(v.Name), Algorithm: render.ViewKeyAlgorithm, Secret: render.ViewKeySecret(x.ViewKeySeed, v.ID)}
 }
+
+// GeneratedStatements lists what Jarl adds to named.conf by itself
+// (render.GeneratedStatements).
+func (e *Engine) GeneratedStatements(ctx context.Context, st *model.State) []render.Generated {
+	return render.GeneratedStatements(st, e.cfg.Paths, e.extras(ctx))
+}

internal/mailcheck/mailcheck.go

@@ -0,0 +1,339 @@
+// Package mailcheck checks the reverse DNS of the addresses that send and
+// receive mail for your public zones (docs/exposure.md#mail): receivers
+// such as Gmail and Outlook reject or mark mail from an address without a
+// PTR record, or whose PTR name doesn't resolve back to it. Those records
+// belong to whoever owns the address (your hosting provider or ISP), not
+// to Jarl, so the check asks the internet and says who to ask.
+package mailcheck
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/netip"
+	"slices"
+	"strings"
+	"time"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/publicsuffix"
+
+	"jarl/internal/model"
+)
+
+// Target is an address mail comes from or goes to, and why it is checked.
+type Target struct {
+	Zone    string   `json:"zone"`
+	Address string   `json:"address"`
+	Roles   []string `json:"roles"`          // e.g. "MX mail.adbraun.lol", "SPF ip4"
+	Host    string   `json:"host,omitempty"` // the MX host name, when it is one
+}
+
+// Result is the check of one address.
+type Result struct {
+	Target
+	PTR []string `json:"ptr"` // the names its PTR records give
+	// OK: a PTR name resolves back to the address (forward-confirmed).
+	OK bool `json:"ok"`
+	// Level is ok, info or warning; Message says what to do.
+	Level   string `json:"level"`
+	Message string `json:"message"`
+	// ReverseZone and ManagedBy say where the PTR record lives.
+	ReverseZone string `json:"reverse_zone,omitempty"`
+	ManagedBy   string `json:"managed_by,omitempty"`
+	// LocalZone is a reverse zone for the address in Jarl ("view/zone"),
+	// which the internet doesn't ask unless the address's owner delegated
+	// it to this server.
+	LocalZone string `json:"local_zone,omitempty"`
+}
+
+// Report is a whole check.
+type Report struct {
+	Checked time.Time `json:"checked"`
+	Results []Result  `json:"results"`
+	// Errors are lookups that failed (no internet, say).
+	Errors []string `json:"errors,omitempty"`
+}
+
+// Targets finds the addresses to check in the public zones: the MX hosts
+// (receiving) and the SPF record's addresses (sending). Names are looked
+// up later, through the resolver.
+func Targets(st *model.State, public func(viewID int64) bool) (addrs []Target, names []Target) {
+	for _, z := range st.SortedZones() {
+		if z.Type != model.ZonePrimary || z.Disabled || !public(z.ViewID) {
+			continue
+		}
+		zone := strings.TrimSuffix(z.Name, ".")
+		for _, r := range st.ZoneRecords(z.ID) {
+			if r.Name != z.Name || r.Disabled {
+				continue
+			}
+			switch r.Type {
+			case "MX":
+				f := strings.Fields(r.Data)
+				if len(f) == 2 && f[1] != "." {
+					names = append(names, Target{Zone: zone, Host: strings.TrimSuffix(strings.ToLower(f[1]), "."), Roles: []string{"MX " + strings.TrimSuffix(f[1], ".")}})
+				}
+			case "TXT":
+				text := strings.ReplaceAll(strings.ReplaceAll(r.Data, `" "`, ""), `"`, "")
+				if !strings.HasPrefix(strings.ToLower(text), "v=spf1") {
+					continue
+				}
+				for _, mech := range strings.Fields(text)[1:] {
+					m := strings.ToLower(strings.TrimLeft(mech, "+?~"))
+					switch {
+					case strings.HasPrefix(m, "ip4:"), strings.HasPrefix(m, "ip6:"):
+						v := m[4:]
+						p, err := netip.ParsePrefix(v)
+						if err != nil {
+							if a, err := netip.ParseAddr(v); err == nil {
+								p = netip.PrefixFrom(a, a.BitLen())
+							} else {
+								continue
+							}
+						}
+						if p.IsSingleIP() {
+							addrs = append(addrs, Target{Zone: zone, Address: p.Addr().String(), Roles: []string{"SPF " + m[:3]}})
+						}
+					case m == "a":
+						names = append(names, Target{Zone: zone, Host: zone, Roles: []string{"SPF a"}})
+					case strings.HasPrefix(m, "a:"):
+						names = append(names, Target{Zone: zone, Host: strings.TrimSuffix(m[2:], "."), Roles: []string{"SPF " + m}})
+					}
+				}
+			}
+		}
+	}
+	return addrs, names
+}
+
+// Resolver asks recursive resolvers (the public ones of acme.resolvers).
+type Resolver struct {
+	Servers []string
+	Timeout time.Duration
+}
+
+func (r Resolver) query(ctx context.Context, name string, qtype uint16) (*dns.Msg, error) {
+	if len(r.Servers) == 0 {
+		return nil, errors.New("no resolvers configured (acme.resolvers)")
+	}
+	m := new(dns.Msg)
+	m.SetQuestion(dns.Fqdn(name), qtype)
+	m.RecursionDesired = true
+	m.SetEdns0(1232, false)
+	t := r.Timeout
+	if t == 0 {
+		t = 5 * time.Second
+	}
+	var last error
+	for _, s := range r.Servers {
+		in, _, err := (&dns.Client{Timeout: t}).ExchangeContext(ctx, m, s)
+		if err == nil && in.Truncated {
+			in, _, err = (&dns.Client{Timeout: t, Net: "tcp"}).ExchangeContext(ctx, m, s)
+		}
+		if err == nil && in.Rcode != dns.RcodeServerFailure && in.Rcode != dns.RcodeRefused {
+			return in, nil
+		}
+		if err != nil {
+			last = fmt.Errorf("%s: %w", s, err)
+		} else {
+			last = fmt.Errorf("%s answered %s", s, dns.RcodeToString[in.Rcode])
+		}
+	}
+	return nil, fmt.Errorf("looking up %s %s: %w", strings.TrimSuffix(name, "."), dns.TypeToString[qtype], last)
+}
+
+// addresses returns a name's A and AAAA addresses (after CNAMEs).
+func (r Resolver) addresses(ctx context.Context, name string) ([]netip.Addr, bool, error) {
+	var out []netip.Addr
+	alias := false
+	for _, t := range []uint16{dns.TypeA, dns.TypeAAAA} {
+		in, err := r.query(ctx, name, t)
+		if err != nil {
+			return nil, false, err
+		}
+		for _, rr := range in.Answer {
+			switch v := rr.(type) {
+			case *dns.A:
+				a, _ := netip.AddrFromSlice(v.A.To4())
+				out = append(out, a)
+			case *dns.AAAA:
+				a, _ := netip.AddrFromSlice(v.AAAA)
+				out = append(out, a)
+			case *dns.CNAME:
+				alias = true
+			}
+		}
+	}
+	return out, alias, nil
+}
+
+// Check looks up every target's reverse DNS.
+func Check(ctx context.Context, st *model.State, public func(int64) bool, res Resolver) *Report {
+	rep := &Report{Checked: time.Now(), Results: []Result{}}
+	addrs, names := Targets(st, public)
+	// Names to addresses, as the internet sees them.
+	for _, n := range names {
+		as, _, err := res.addresses(ctx, n.Host)
+		if err != nil {
+			rep.Errors = append(rep.Errors, err.Error())
+			continue
+		}
+		if len(as) == 0 {
+			rep.Errors = append(rep.Errors, fmt.Sprintf("%s (%s, %s) has no address as the internet sees it: not published yet, or a typo?", n.Host, n.Zone, strings.Join(n.Roles, ", ")))
+		}
+		for _, a := range as {
+			t := n
+			t.Address = a.String()
+			addrs = append(addrs, t)
+		}
+	}
+	// One result per address, with every reason it is checked.
+	merged := map[string]*Target{}
+	var order []string
+	for _, t := range addrs {
+		k := t.Zone + "|" + t.Address
+		if m := merged[k]; m != nil {
+			for _, role := range t.Roles {
+				if !slices.Contains(m.Roles, role) {
+					m.Roles = append(m.Roles, role)
+				}
+			}
+			if m.Host == "" {
+				m.Host = t.Host
+			}
+			continue
+		}
+		t := t
+		merged[k] = &t
+		order = append(order, k)
+	}
+	for _, k := range order {
+		r := checkOne(ctx, *merged[k], res)
+		r.LocalZone = localReverse(st, r.Address, r.ReverseZone)
+		rep.Results = append(rep.Results, r)
+	}
+	return rep
+}
+
+// localReverse returns a reverse zone in Jarl that covers the address,
+// unless it is the zone the internet asks (delegated to this server).
+func localReverse(st *model.State, addr, internetZone string) string {
+	rev, err := dns.ReverseAddr(addr)
+	if err != nil {
+		return ""
+	}
+	rev = strings.ToLower(rev)
+	best := ""
+	var bz *model.Zone
+	for _, z := range st.SortedZones() {
+		n := strings.ToLower(dns.Fqdn(z.Name))
+		if z.Type == model.ZonePrimary && dns.IsSubDomain(n, rev) && len(n) > len(best) {
+			best, bz = n, z
+		}
+	}
+	if bz == nil || strings.EqualFold(strings.TrimSuffix(best, "."), internetZone) {
+		return ""
+	}
+	if v := st.ViewName(bz); v != "" {
+		return v + "/" + strings.TrimSuffix(bz.Name, ".")
+	}
+	return strings.TrimSuffix(bz.Name, ".")
+}
+
+func checkOne(ctx context.Context, t Target, res Resolver) Result {
+	r := Result{Target: t, PTR: []string{}}
+	a, err := netip.ParseAddr(t.Address)
+	if err != nil {
+		r.Level, r.Message = "warning", err.Error()
+		return r
+	}
+	rev, _ := dns.ReverseAddr(a.String())
+	in, err := res.query(ctx, rev, dns.TypePTR)
+	if err != nil {
+		r.Level, r.Message = "warning", err.Error()
+		return r
+	}
+	// Who manages the reverse zone: the SOA in the answer.
+	for _, sec := range [][]dns.RR{in.Ns, in.Answer} {
+		for _, rr := range sec {
+			if soa, ok := rr.(*dns.SOA); ok {
+				r.ReverseZone, r.ManagedBy = strings.TrimSuffix(soa.Hdr.Name, "."), managedBy(soa.Ns)
+			}
+		}
+	}
+	if r.ReverseZone == "" {
+		if s, err := res.query(ctx, rev, dns.TypeSOA); err == nil {
+			for _, sec := range [][]dns.RR{s.Answer, s.Ns} {
+				for _, rr := range sec {
+					if soa, ok := rr.(*dns.SOA); ok {
+						r.ReverseZone, r.ManagedBy = strings.TrimSuffix(soa.Hdr.Name, "."), managedBy(soa.Ns)
+					}
+				}
+			}
+		}
+	}
+	for _, rr := range in.Answer {
+		if p, ok := rr.(*dns.PTR); ok {
+			r.PTR = append(r.PTR, strings.TrimSuffix(strings.ToLower(p.Ptr), "."))
+		}
+	}
+	where := "whoever runs the address's reverse zone (your hosting provider or ISP)"
+	if r.ManagedBy != "" {
+		where = "the reverse zone's owner (" + r.ManagedBy + ": your hosting provider's or ISP's panel)"
+	}
+	if len(r.PTR) == 0 {
+		r.Level = "warning"
+		r.Message = fmt.Sprintf("%s has no PTR record: many receivers reject or mark mail from it. Set its reverse DNS to %s at %s", t.Address, suggestName(t), where)
+		return r
+	}
+	var notes []string
+	for _, name := range r.PTR {
+		as, alias, err := res.addresses(ctx, name)
+		if err != nil {
+			notes = append(notes, err.Error())
+			continue
+		}
+		if slices.Contains(as, a) {
+			r.OK = true
+			if alias {
+				notes = append(notes, name+" is an alias (CNAME): receivers expect the PTR to name a host with its own A/AAAA record")
+			}
+			if t.Host != "" && name != t.Host && strings.HasPrefix(strings.Join(t.Roles, " "), "MX") {
+				notes = append(notes, fmt.Sprintf("the PTR name is %s, not the MX name %s: fine if the mail server says %s in HELO", name, t.Host, name))
+			}
+		}
+	}
+	switch {
+	case !r.OK:
+		r.Level = "warning"
+		r.Message = fmt.Sprintf("the PTR record of %s names %s, which doesn't resolve back to %s: receivers check that it does. Point the PTR at a name with an A/AAAA record for %s (set at %s), or add that record", t.Address, strings.Join(r.PTR, ", "), t.Address, t.Address, where)
+	case len(notes) > 0:
+		r.Level, r.Message = "info", strings.Join(notes, "; ")
+	default:
+		r.Level, r.Message = "ok", fmt.Sprintf("%s → %s → %s", t.Address, strings.Join(r.PTR, ", "), t.Address)
+	}
+	return r
+}
+
+func suggestName(t Target) string {
+	if t.Host != "" {
+		return t.Host
+	}
+	return "the host's name (with an A/AAAA record for it)"
+}
+
+// managedBy turns the reverse zone's primary name server into its owner's
+// domain: ns1.linode.com -> linode.com, dns0.zen.co.uk -> zen.co.uk.
+func managedBy(ns string) string {
+	ns = strings.TrimSuffix(strings.ToLower(ns), ".")
+	labels := strings.Split(ns, ".")
+	// The registered domain under the ICANN suffix: the list's private
+	// part (members.linode.com) names customers, not the provider.
+	for i := 1; i < len(labels); i++ {
+		if suffix, icann := publicsuffix.PublicSuffix(strings.Join(labels[i:], ".")); icann && suffix == strings.Join(labels[i:], ".") {
+			return strings.Join(labels[i-1:], ".")
+		}
+	}
+	return ns
+}

internal/mailcheck/mailcheck_test.go

@@ -0,0 +1,108 @@
+package mailcheck
+
+import (
+	"context"
+	"net"
+	"strings"
+	"testing"
+
+	"github.com/miekg/dns"
+
+	"jarl/internal/model"
+)
+
+// fakeResolver answers from a fixed set of records, as a recursive
+// resolver would, with the reverse zone's SOA in negative answers.
+func fakeResolver(t *testing.T, records ...string) string {
+	t.Helper()
+	var rrs []dns.RR
+	for _, s := range records {
+		rr, err := dns.NewRR(s)
+		if err != nil {
+			t.Fatal(err)
+		}
+		rrs = append(rrs, rr)
+	}
+	soa, _ := dns.NewRR("2.0.192.in-addr.arpa. 3600 IN SOA ns1.linode.com. hostmaster.linode.com. 1 3600 900 1209600 300")
+	pc, err := net.ListenPacket("udp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	srv := &dns.Server{PacketConn: pc, Handler: dns.HandlerFunc(func(w dns.ResponseWriter, q *dns.Msg) {
+		m := new(dns.Msg)
+		m.SetReply(q)
+		qn := strings.ToLower(q.Question[0].Name)
+		for _, rr := range rrs {
+			if strings.ToLower(rr.Header().Name) == qn && (rr.Header().Rrtype == q.Question[0].Qtype || rr.Header().Rrtype == dns.TypeCNAME) {
+				m.Answer = append(m.Answer, rr)
+			}
+		}
+		if len(m.Answer) == 0 && dns.IsSubDomain(soa.Header().Name, qn) {
+			if q.Question[0].Qtype == dns.TypeSOA && qn == soa.Header().Name {
+				m.Answer = append(m.Answer, soa)
+			} else {
+				m.Ns = append(m.Ns, soa)
+			}
+		}
+		w.WriteMsg(m)
+	})}
+	go srv.ActivateAndServe()
+	t.Cleanup(func() { srv.Shutdown() })
+	return pc.LocalAddr().String()
+}
+
+func TestCheck(t *testing.T) {
+	st := model.NewState()
+	ext := &model.View{ID: 1, Name: "external", MatchClients: []string{"any"}}
+	in := &model.View{ID: 2, Name: "internal", MatchClients: []string{"lan"}}
+	st.Views[1], st.Views[2] = ext, in
+	z := &model.Zone{ID: 10, Name: "example.com.", ViewID: 1, Type: model.ZonePrimary}
+	zi := &model.Zone{ID: 11, Name: "example.com.", ViewID: 2, Type: model.ZonePrimary}
+	rev := &model.Zone{ID: 12, Name: "27.2.0.192.in-addr.arpa.", ViewID: 2, Type: model.ZonePrimary}
+	st.Zones[10], st.Zones[11], st.Zones[12] = z, zi, rev
+	rec := func(id, zone int64, name, typ, data string) {
+		st.Records[id] = &model.Record{ID: id, ZoneID: zone, Name: name, Type: typ, Data: data}
+	}
+	rec(1, 10, "example.com.", "MX", "10 mail.example.com.")
+	rec(2, 10, "example.com.", "TXT", `"v=spf1 mx ip4:192.0.2.26 ip4:192.0.2.27" " ip4:198.51.100.0/24 -all"`)
+	rec(3, 10, "www.example.com.", "MX", "10 ignored.example.com.") // not the apex
+	rec(4, 11, "example.com.", "MX", "10 internal.example.com.")    // private view
+	rec(5, 10, "example.com.", "TXT", `"google-site-verification=x"`)
+	rec(6, 10, "example.com.", "MX", "20 backup.example.com.") // not on the internet
+
+	res := Resolver{Servers: []string{fakeResolver(t,
+		"mail.example.com. 300 IN A 192.0.2.25",
+		"25.2.0.192.in-addr.arpa. 300 IN PTR mail.example.com.",
+		"27.2.0.192.in-addr.arpa. 300 IN PTR li-27.members.linode.com.",
+		"li-27.members.linode.com. 300 IN A 192.0.2.99",
+	)}}
+	public := func(id int64) bool { return id == 1 }
+	rep := Check(context.Background(), st, public, res)
+	if len(rep.Errors) != 1 || !strings.Contains(rep.Errors[0], "backup.example.com (example.com, MX backup.example.com) has no address") {
+		t.Fatalf("errors %v", rep.Errors)
+	}
+	got := map[string]Result{}
+	for _, r := range rep.Results {
+		got[r.Address] = r
+	}
+	if len(got) != 3 {
+		t.Fatalf("results %+v", rep.Results)
+	}
+	if r := got["192.0.2.25"]; !r.OK || r.Level != "ok" || r.Roles[0] != "MX mail.example.com" || r.ManagedBy != "" && r.ManagedBy != "linode.com" {
+		t.Errorf("mail: %+v", r)
+	}
+	if r := got["192.0.2.26"]; r.OK || r.Level != "warning" || !strings.Contains(r.Message, "no PTR record") || r.ManagedBy != "linode.com" || r.ReverseZone != "2.0.192.in-addr.arpa" {
+		t.Errorf("no PTR: %+v", r)
+	}
+	if r := got["192.0.2.27"]; r.OK || !strings.Contains(r.Message, "doesn't resolve back") || r.LocalZone != "internal/27.2.0.192.in-addr.arpa" {
+		t.Errorf("not forward-confirmed: %+v", r)
+	}
+}
+
+func TestManagedBy(t *testing.T) {
+	for in, want := range map[string]string{"ns1.linode.com.": "linode.com", "dns0.zen.co.uk.": "zen.co.uk", "ns1.members.linode.com.": "linode.com", "localhost.": "localhost"} {
+		if got := managedBy(in); got != want {
+			t.Errorf("managedBy(%q) = %q, want %q", in, got, want)
+		}
+	}
+}

internal/model/model.go

@@ -54,6 +54,11 @@ type View struct {
 	// internet (docs/exposure.md): "" works it out, ExposurePublic or
 	// ExposurePrivate say so.
 	Exposure string `json:"exposure,omitempty"`
+	// ReverseSuggestionsOff stops suggesting reverse zones for the view's
+	// addresses (docs/reverse.md), e.g. for a view only a few servers use;
+	// DismissedReverse are the networks whose suggestion was dismissed.
+	ReverseSuggestionsOff bool     `json:"reverse_suggestions_off,omitempty"`
+	DismissedReverse      []string `json:"dismissed_reverse,omitempty"`
 	// Acknowledged are exposure findings accepted on purpose; they are
 	// shown as info instead of warnings.
 	Acknowledged []Acknowledgement `json:"acknowledged,omitempty"`
@@ -170,6 +175,10 @@ type Zone struct {
 	// keeps their shared records in step (docs/views.md#linked-zones). 0
 	// for a zone that isn't linked; linked zones share the ID.
 	LinkGroup int64 `json:"link_group,omitempty"`
+	// AutoPTR keeps the PTR records of the zone's A and AAAA records in
+	// step with them, in the reverse zones of the zone's views, as if every
+	// change asked for it (docs/reverse.md).
+	AutoPTR bool `json:"auto_ptr,omitempty"`
 	Meta
 }
 
@@ -263,7 +272,10 @@ type Settings struct {
 	// for server-wide findings such as a visible version): see View.
 	Exposure     string            `json:"exposure,omitempty"`
 	Acknowledged []Acknowledgement `json:"acknowledged,omitempty"`
-	Version      int               `json:"version"`
+	// DismissedReverse are dismissed reverse zone suggestions (without
+	// views; see View).
+	DismissedReverse []string `json:"dismissed_reverse,omitempty"`
+	Version          int      `json:"version"`
 }
 
 // BlockingPaused reports whether blocking is paused, for a time or until

internal/namedconf/printer.go

@@ -182,3 +182,38 @@ func writeItemsInline(sb *strings.Builder, items []Item) {
 		}
 	}
 }
+
+// FormatValueList is FormatValue, except that a value whose block is a
+// plain list (no nested blocks) of at least min elements is laid out one
+// element per line, for reading: allow-query, exempt-clients, forwarders.
+func FormatValueList(name, value string, min int) string {
+	st, err := ParseOptionValue(name, value)
+	if err != nil {
+		return FormatValue(name, value)
+	}
+	items := st.Items[1:]
+	blocks := 0
+	var list *Block
+	for _, it := range items {
+		if it.Block != nil {
+			blocks++
+			list = it.Block
+		}
+	}
+	if blocks != 1 || len(list.Stmts) < min || blockHasBlocks(list) {
+		return FormatValue(name, value)
+	}
+	var sb strings.Builder
+	for _, it := range items {
+		if it.Block == nil {
+			sb.WriteString(Compact([]Item{it}) + " ")
+			continue
+		}
+		sb.WriteString("{\n")
+		for _, s := range list.Stmts {
+			sb.WriteString("\t" + Compact(s.Items) + ";\n")
+		}
+		sb.WriteString("} ")
+	}
+	return strings.TrimSpace(sb.String())
+}

internal/namedconf/printer_test.go

@@ -16,3 +16,23 @@ func TestFormatValue(t *testing.T) {
 		}
 	}
 }
+
+func TestFormatValueList(t *testing.T) {
+	cases := []struct{ name, value, want string }{
+		{"allow-query", "{ homelab; localhost; 10.0.0.0/8; }", "{\n\thomelab;\n\tlocalhost;\n\t10.0.0.0/8;\n}"},
+		{"allow-query", "{ homelab; localhost; }", "{ homelab; localhost; }"}, // short: as it was
+		{"listen-on", "port 853 tls dot { 10.0.0.1; 10.0.0.2; 10.0.0.3; }", "port 853 tls dot {\n\t10.0.0.1;\n\t10.0.0.2;\n\t10.0.0.3;\n}"},
+		{"allow-transfer", "{ !10.0.0.9; key xfer; 10.0.0.0/8; }", "{\n\t!10.0.0.9;\n\tkey xfer;\n\t10.0.0.0/8;\n}"},
+		{"recursion", "yes", "yes"},
+	}
+	for _, c := range cases {
+		if got := FormatValueList(c.name, c.value, 3); got != c.want {
+			t.Errorf("%s %q:\n got %q\nwant %q", c.name, c.value, got, c.want)
+		}
+	}
+	// A nested block (rate-limit with exempt-clients) keeps FormatValue's layout.
+	v := "{ responses-per-second 10; log-only yes; exempt-clients { 192.0.2.1; 192.0.2.2; 192.0.2.3; }; }"
+	if got := FormatValueList("rate-limit", v, 3); got != FormatValue("rate-limit", v) {
+		t.Errorf("nested: %q", got)
+	}
+}

internal/render/generated.go

@@ -0,0 +1,142 @@
+package render
+
+import (
+	"strings"
+
+	"jarl/internal/model"
+	"jarl/internal/namedconf"
+)
+
+// Generated is a statement Jarl adds to named's configuration by itself,
+// not from an option you set: why, and what controls it.
+type Generated struct {
+	Where   string `json:"where"`   // top level, options, or "view NAME"
+	Text    string `json:"text"`    // as written in named.conf
+	Why     string `json:"why"`     // what it is for
+	Setting string `json:"setting"` // what turns it on or off
+}
+
+// GeneratedStatements lists what Render adds to named.conf beyond the
+// options in the database, so nothing there comes as a surprise.
+func GeneratedStatements(s *model.State, p Paths, x Extras) []Generated {
+	var out []Generated
+	add := func(where, text, why, setting string) {
+		out = append(out, Generated{Where: where, Text: strings.TrimRight(text, "\n"), Why: why, Setting: setting})
+	}
+	add("top level", "include "+namedconf.QuoteString(p.KeysConfig())+";",
+		"TSIG keys (and the view keys) live in their own file, which only named and jarld can read", "always")
+	st := x.Stats
+	logResponses := st != nil && st.LogFile != ""
+	pzs := PolicyZones(s, p)
+	if st != nil {
+		_, user := findTop(s, "statistics-channels")
+		why := "named publishes its counters for jarld's query statistics, on a loopback address only"
+		if user {
+			why += " (added to your statistics-channels statement)"
+		}
+		add("top level", formatStmt(namedconf.NewStmt("statistics-channels", namedconf.NewBlock(st.statsInet())), 0), why, "stats.enabled in jarl.yaml")
+	}
+	if logResponses {
+		b := namedconf.NewBlock(st.logChannel())
+		cat := func(name string, extra ...string) {
+			ch := namedconf.NewBlock(namedconf.NewStmt(StatsChannelName))
+			for _, e := range extra {
+				ch.Stmts = append(ch.Stmts, namedconf.NewStmt(e))
+			}
+			b.Stmts = append(b.Stmts, namedconf.NewStmt("category", name, ch))
+		}
+		why := []string{"responses: every answer, for the statistics' names, clients and views"}
+		cat("responses")
+		if len(pzs) > 0 {
+			cat("rpz")
+			why = append(why, "rpz: what blocking blocked")
+		}
+		if logRateLimit(s, st) {
+			cat("query-errors", "default_syslog")
+			why = append(why, "query-errors: what rate limiting limited, or would in log-only mode, for the Exposure page (also to syslog, as before)")
+		}
+		w := "named logs to a file jarld reads (" + strings.Join(why, "; ") + ")"
+		if _, user := findTop(s, "logging"); user {
+			w += "; merged into your logging statement"
+		}
+		setting := "stats.query_log in jarl.yaml"
+		if logRateLimit(s, st) || hasRateLimit(s) {
+			setting += "; query-errors: stats.rate_limit_log"
+		}
+		add("top level", formatStmt(namedconf.NewStmt("logging", b), 0), w, setting)
+		if s.FindOption(model.ScopeOptions, 0, "responselog") == nil {
+			add("options", "responselog yes;", "named logs answers from the start, for the statistics", "stats.query_log in jarl.yaml")
+		}
+	}
+	views := s.OrderedViews()
+	scopes := []struct {
+		id   int64
+		name string
+	}{{0, "options"}}
+	if len(views) > 0 {
+		scopes = scopes[:0]
+		for _, v := range views {
+			scopes = append(scopes, struct {
+				id   int64
+				name string
+			}{v.ID, "view " + v.Name})
+		}
+	}
+	for _, sc := range scopes {
+		zs := scopeZones(pzs, sc.id)
+		if len(zs) == 0 {
+			continue
+		}
+		w := newConfWriter()
+		writeResponsePolicy(w, zs, logResponses)
+		writePolicyZones(w, s, zs, &Output{}, 0)
+		add(sc.name, dedent(w.sb.String()), "blocking: your rules and blocklists, as response policy zones named loads", "the Blocking page (jarl block, jarl blocklist)")
+	}
+	if viewKeysOn(s, Extras{ViewKeySeed: x.ViewKeySeed}) {
+		for _, v := range views {
+			mc := viewMatchClients(s, x, v)
+			var keys []string
+			for _, e := range mc {
+				if strings.Contains(e, "key ") {
+					keys = append(keys, e+";")
+				}
+			}
+			add("view "+v.Name, "match-clients { "+strings.Join(keys, " ")+" ... };",
+				"view keys: a query signed with a view's key gets that view, from any address, and never another view (jarl view key)", "always, when there are views")
+		}
+	}
+	return out
+}
+
+func findTop(s *model.State, name string) (*model.Option, bool) {
+	for _, o := range s.ScopedOptions(model.ScopeTopLevel, 0) {
+		if o.Name == name {
+			return o, true
+		}
+	}
+	return nil, false
+}
+
+func hasRateLimit(s *model.State) bool {
+	for _, o := range s.Options {
+		if o.Name == "rate-limit" {
+			return true
+		}
+	}
+	return false
+}
+
+// logRateLimit reports whether rate limiting's log lines go to the
+// response log (docs/exposure.md).
+func logRateLimit(s *model.State, st *StatsHooks) bool {
+	return st != nil && st.LogFile != "" && !st.NoRateLimitLog && hasRateLimit(s)
+}
+
+// dedent removes one leading tab from every line.
+func dedent(s string) string {
+	lines := strings.Split(s, "\n")
+	for i, l := range lines {
+		lines[i] = strings.TrimPrefix(l, "\t")
+	}
+	return strings.Join(lines, "\n")
+}

internal/render/render.go

@@ -274,10 +274,7 @@ func renderConfig(s *model.State, p Paths, x Extras, out *Output) (string, []Spa
 	logRewrites := logResponses && len(pzs) > 0
 	// Rate limiting logs what it limits (or would, in log-only mode) as
 	// query-errors; the statistics count it (docs/exposure.md).
-	logRRL := false
-	for _, o := range s.Options {
-		logRRL = logRRL || logResponses && o.Name == "rate-limit"
-	}
+	logRRL := logRateLimit(s, st)
 	sawStats, sawLogging := false, false
 	if top := s.ScopedOptions(model.ScopeTopLevel, 0); len(top) > 0 {
 		w.write("\n")

internal/render/stats.go

@@ -26,6 +26,9 @@ type StatsHooks struct {
 	LogFile     string         // response log; "" disables response logging
 	LogVersions int
 	LogSize     string
+	// NoRateLimitLog keeps rate limiting's log lines (category
+	// query-errors) out of the response log (stats.rate_limit_log: false).
+	NoRateLimitLog bool
 }
 
 // StatsChannelName is the logging channel Jarl adds for responses.

internal/render/stats_test.go

@@ -82,3 +82,45 @@ func TestStatsHooksMerged(t *testing.T) {
 func TestStatsHooksWithNamed(t *testing.T) {
 	checkWithNamed(t, sampleState(t), Extras{Stats: statsHooks()})
 }
+
+// Rate limiting's log lines go to the response log unless
+// stats.rate_limit_log is off; the list of what Jarl adds says so.
+func TestRateLimitLogAndGenerated(t *testing.T) {
+	s := sampleState(t)
+	for id, o := range s.Options {
+		if o.Name == "logging" {
+			delete(s.Options, id)
+		}
+	}
+	s.Options[20000] = &model.Option{ID: 20000, Scope: model.ScopeOptions, Name: "rate-limit", Value: "{ responses-per-second 10; log-only yes; }", Position: 20000}
+	p := Paths{ConfigDir: "/etc/bind/jarl", ZoneDir: "/var/lib/bind/jarl", CacheDir: "/var/cache/bind/jarl"}
+	conf := string(Render(s, p, Extras{Stats: statsHooks()}).File(p.MainConfig()).Content)
+	if !strings.Contains(conf, "category query-errors { jarl_responses; default_syslog; };") {
+		t.Errorf("query-errors not logged:\n%s", conf)
+	}
+	gen := GeneratedStatements(s, p, Extras{Stats: statsHooks()})
+	var logging *Generated
+	for i := range gen {
+		if strings.HasPrefix(gen[i].Text, "logging") {
+			logging = &gen[i]
+		}
+	}
+	if logging == nil || !strings.Contains(logging.Text, "query-errors") || !strings.Contains(logging.Setting, "stats.rate_limit_log") {
+		t.Errorf("generated logging = %+v (all %+v)", logging, gen)
+	}
+	if !strings.HasPrefix(gen[0].Text, "include ") || gen[0].Where != "top level" {
+		t.Errorf("first generated = %+v", gen[0])
+	}
+
+	h := statsHooks()
+	h.NoRateLimitLog = true
+	conf = string(Render(s, p, Extras{Stats: h}).File(p.MainConfig()).Content)
+	if strings.Contains(conf, "query-errors") || !strings.Contains(conf, "category responses") {
+		t.Errorf("rate_limit_log off but query-errors logged:\n%s", conf)
+	}
+	for _, g := range GeneratedStatements(s, p, Extras{Stats: h}) {
+		if strings.Contains(g.Text, "query-errors") {
+			t.Errorf("listed while off: %+v", g)
+		}
+	}
+}

internal/server/h_compare.go

@@ -9,15 +9,29 @@ import (
 	"jarl/internal/model"
 )
 
-// zoneCompare: GET /zones/{zone}/compare lines up a zone's records across
-// the views that have it (docs/views.md#linked-zones). ?views=a,b picks the
-// views (default: every view with a primary zone of that name), ?all=1
-// includes the names and types that are the same everywhere.
+// zoneCompare: GET /zones/{zone}/compare compares a zone with the same
+// zone in other views (docs/views.md#comparing-views), from the zone's own
+// view: ?with=a,b picks the other views (default: every view with a
+// primary zone of that name), ?name=www[&type=A] narrows it to one name,
+// ?all=1 includes what is the same. A zone named without its view is
+// compared from the first view that has it. (?views=a,b, the views to
+// compare with the first as the base, works too.)
 func (s *Server) zoneCompare(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
 	st, err := s.state(r)
 	if err != nil {
 		return err
 	}
+	q := r.URL.Query()
+	list := func(k string) []string {
+		var out []string
+		for _, v := range strings.Split(q.Get(k), ",") {
+			if v = strings.TrimSpace(v); v != "" {
+				out = append(out, v)
+			}
+		}
+		return out
+	}
+	with, views := list("with"), list("views")
 	z, err := s.zoneByPath(r, st, p)
 	if err != nil {
 		// A name in several views is what there is to compare.
@@ -26,56 +40,45 @@ func (s *Server) zoneCompare(w http.ResponseWriter, r *http.Request, p *auth.Pri
 			ref = "."
 		}
 		name, perr := engine.ParseZoneName(ref)
-		if zs := st.ZonesNamed(name); perr != nil || len(zs) < 2 {
+		zs := st.ZonesNamed(name)
+		if perr != nil || len(zs) < 2 {
 			return err
-		} else {
-			z = zs[0]
+		}
+		st.SortByView(zs)
+		z = zs[0]
+		if len(views) > 0 {
+			for _, o := range zs {
+				if strings.EqualFold(st.ViewName(o), views[0]) {
+					z = o
+				}
+			}
 		}
 	}
-	var want []string
-	for _, v := range strings.Split(r.URL.Query().Get("views"), ",") {
-		if v = strings.TrimSpace(v); v != "" {
-			want = append(want, v)
-		}
+	readable := func(o *model.Zone) bool {
+		vn := st.ViewName(o)
+		return o.Type == model.ZonePrimary && p.CanSeeZone(o.Name, vn) && p.Can(auth.Action{Resource: auth.ResRecords, Zone: o.Name, View: vn})
 	}
-	var zones []*model.Zone
+	if !readable(z) {
+		return badRequest("zone %s isn't a primary zone whose records you may read", engine.Display(z.Name))
+	}
+	zones := []*model.Zone{z}
+	var others []*model.Zone
 	for _, o := range st.ZonesNamed(z.Name) {
 		vn := st.ViewName(o)
-		if o.Type != model.ZonePrimary || !p.CanSeeZone(o.Name, vn) || !p.Can(auth.Action{Resource: auth.ResRecords, Zone: o.Name, View: vn}) {
+		if o.ID == z.ID || !readable(o) {
 			continue
 		}
-		if len(want) > 0 && !containsFold(want, vn) {
+		if len(with) > 0 && !containsFold(with, vn) || len(views) > 0 && !containsFold(views, vn) {
 			continue
 		}
-		zones = append(zones, o)
+		others = append(others, o)
 	}
-	st.SortByView(zones)
+	st.SortByView(others)
+	zones = append(zones, others...)
 	if len(zones) < 2 {
 		return badRequest("zone %s is in only one view (that you may read): there is nothing to compare", engine.Display(z.Name))
 	}
-	rows := engine.CompareZones(st, zones)
-	all := queryBool(r, "all")
-	out := struct {
-		Zone   string              `json:"zone"`
-		Views  []string            `json:"views"`
-		Linked bool                `json:"linked"` // all of them in one link
-		Same   int                 `json:"same"`   // names and types the same everywhere
-		Rows   []engine.CompareRow `json:"rows"`
-	}{Zone: engine.Display(z.Name), Rows: []engine.CompareRow{}, Linked: true}
-	for _, o := range zones {
-		out.Views = append(out.Views, st.ViewName(o))
-		out.Linked = out.Linked && o.LinkGroup != 0 && o.LinkGroup == zones[0].LinkGroup
-	}
-	for _, row := range rows {
-		if row.Same {
-			out.Same++
-			if !all {
-				continue
-			}
-		}
-		out.Rows = append(out.Rows, row)
-	}
-	writeJSON(w, http.StatusOK, out)
+	writeJSON(w, http.StatusOK, engine.Compare(st, zones, engine.CompareFilter{Name: q.Get("name"), Type: q.Get("type"), All: queryBool(r, "all")}))
 	return nil
 }
 

internal/server/h_config.go

@@ -659,3 +659,22 @@ func (s *Server) search(w http.ResponseWriter, r *http.Request, p *auth.Principa
 	writeJSON(w, http.StatusOK, out)
 	return nil
 }
+
+// generatedOptions: GET /options/generated lists what Jarl adds to
+// named.conf by itself (the statistics channel, its logging, blocking's
+// response-policy, view keys), with why and what controls it.
+func (s *Server) generatedOptions(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	if err := require(p, auth.Action{Resource: auth.ResOptions}); err != nil {
+		return err
+	}
+	st, err := s.store.LoadState(r.Context())
+	if err != nil {
+		return err
+	}
+	out := s.eng.GeneratedStatements(r.Context(), st)
+	if out == nil {
+		out = []render.Generated{}
+	}
+	writeJSON(w, http.StatusOK, out)
+	return nil
+}

internal/server/h_exposure.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"jarl/internal/mailcheck"
 	"net/http"
 	"time"
 
@@ -32,6 +33,11 @@ type exposureReport struct {
 	// RateLimiting is what rate limiting limited, or would have, in the
 	// last 24 hours (with query statistics on).
 	RateLimiting *rateLimitActivity `json:"rate_limiting,omitempty"`
+	// RateLimitLog is false when stats.rate_limit_log is off: what rate
+	// limiting does isn't counted then.
+	RateLimitLog bool `json:"rate_limit_log"`
+	// Mail is the last check of the mail addresses' reverse DNS.
+	Mail *mailcheck.Report `json:"mail,omitempty"`
 }
 
 type rateLimitActivity struct {
@@ -52,7 +58,7 @@ func (s *Server) exposure(w http.ResponseWriter, r *http.Request, p *auth.Princi
 		return err
 	}
 	problems := s.eng.Validate(st)
-	out := exposureReport{Scopes: []exposureScope{}, Server: []exposureFinding{}}
+	out := exposureReport{Scopes: []exposureScope{}, Server: []exposureFinding{}, RateLimitLog: s.cfg.RateLimitLog}
 	finding := func(pr validate.Problem, viewID int64) exposureFinding {
 		_, desc := engine.ExposureFix(st, viewID, pr.Code)
 		return exposureFinding{Problem: pr, Fix: desc}
@@ -96,6 +102,7 @@ func (s *Server) exposure(w http.ResponseWriter, r *http.Request, p *auth.Princi
 		a.Names, _ = s.statsQ.Top(ctx, stats.KindRateLimitedName, since, 10)
 		out.RateLimiting = a
 	}
+	out.Mail = s.mailReport()
 	writeJSON(w, http.StatusOK, out)
 	return nil
 }

internal/server/h_mail.go

@@ -0,0 +1,83 @@
+package server
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"jarl/internal/auth"
+	"jarl/internal/mailcheck"
+)
+
+// mailCheckEvery is how often jarld checks the reverse DNS of the
+// addresses that send and receive mail (docs/exposure.md#mail).
+const mailCheckEvery = 6 * time.Hour
+
+// checkMail checks the reverse DNS of the public zones' mail addresses and
+// keeps the report; it logs addresses that became wrong.
+func (s *Server) checkMail(ctx context.Context) *mailcheck.Report {
+	st, err := s.store.LoadState(ctx)
+	if err != nil {
+		s.log.Warn("mail reverse DNS check: loading state", "err", err)
+		return nil
+	}
+	public := map[int64]bool{}
+	for _, x := range s.eng.Exposures(st) {
+		public[x.ViewID] = x.Public
+	}
+	if len(st.Views) == 0 {
+		public[0] = true
+	}
+	ctx, cancel := context.WithTimeout(ctx, 2*time.Minute)
+	defer cancel()
+	rep := mailcheck.Check(ctx, st, func(id int64) bool { return public[id] }, mailcheck.Resolver{Servers: s.cfg.Resolvers})
+	s.mail.Lock()
+	prev := s.mail.r
+	s.mail.r = rep
+	s.mail.Unlock()
+	was := map[string]bool{}
+	if prev != nil {
+		for _, r := range prev.Results {
+			was[r.Zone+"|"+r.Address] = r.OK
+		}
+	}
+	for _, r := range rep.Results {
+		if ok, seen := was[r.Zone+"|"+r.Address]; !r.OK && (ok || !seen) {
+			s.log.Warn("mail reverse DNS", "zone", r.Zone, "address", r.Address, "problem", r.Message)
+		}
+	}
+	return rep
+}
+
+func (s *Server) mailReport() *mailcheck.Report {
+	s.mail.Lock()
+	defer s.mail.Unlock()
+	return s.mail.r
+}
+
+// mailCheckNow: POST /exposure/mail checks now and returns the report.
+func (s *Server) mailCheckNow(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	if err := require(p, auth.Action{Resource: auth.ResOptions}); err != nil {
+		return err
+	}
+	rep := s.checkMail(r.Context())
+	if rep == nil {
+		rep = &mailcheck.Report{Checked: time.Now(), Results: []mailcheck.Result{}}
+	}
+	writeJSON(w, http.StatusOK, rep)
+	return nil
+}
+
+// mailLoop checks a minute after the start, then every mailCheckEvery.
+func (s *Server) mailLoop(ctx context.Context) {
+	wait := time.Minute
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(wait):
+			s.checkMail(ctx)
+			wait = mailCheckEvery
+		}
+	}
+}

internal/server/h_reverse.go

@@ -0,0 +1,58 @@
+package server
+
+import (
+	"net/http"
+
+	"jarl/internal/auth"
+	"jarl/internal/engine"
+)
+
+// zoneFillPTR: POST /zones/{zone}/fill-ptr adds the PTR records a reverse
+// zone lacks for its view's A and AAAA records (docs/reverse.md).
+func (s *Server) zoneFillPTR(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	st, err := s.state(r)
+	if err != nil {
+		return err
+	}
+	z, err := s.zoneByPath(r, st, p)
+	if err != nil {
+		return err
+	}
+	return s.mutate(w, r, p, "", []engine.Request{engine.NewRequest(engine.OpZoneFillPTR, z.ID, engine.LinkInput{ZoneID: z.ID})}, nil)
+}
+
+// reverseSuggestions: GET /reverse-zones/suggestions lists the reverse
+// zones the private views lack for their records' addresses. ?all=1 adds
+// the ones not suggested unasked (public views, views with suggestions
+// off, dismissed), marked hidden; ?view= narrows it to one view.
+func (s *Server) reverseSuggestions(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+	st, err := s.state(r)
+	if err != nil {
+		return err
+	}
+	out := []engine.ReverseSuggestion{}
+	for _, sg := range s.eng.ReverseSuggestions(st, engine.ReverseOptions{All: queryBool(r, "all"), View: r.URL.Query().Get("view")}) {
+		if p.CanSeeZone(sg.Zone+".", sg.View) {
+			out = append(out, sg)
+		}
+	}
+	writeJSON(w, http.StatusOK, out)
+	return nil
+}
+
+// reverseDismiss: POST /reverse-zones/dismiss {"view": "internal",
+// "prefix": "185.199.108.153/32"} hides a suggestion; /undismiss shows it
+// again.
+func (s *Server) reverseDismiss(dismiss bool) handler {
+	return func(w http.ResponseWriter, r *http.Request, p *auth.Principal) error {
+		var in engine.DismissInput
+		if err := decodeJSON(r, &in); err != nil {
+			return err
+		}
+		op := engine.OpReverseUndismiss
+		if dismiss {
+			op = engine.OpReverseDismiss
+		}
+		return s.mutate(w, r, p, "", []engine.Request{engine.NewRequest(op, 0, in)}, nil)
+	}
+}

internal/server/metrics.go

@@ -296,6 +296,13 @@ func (s *Server) collectState(ctx context.Context, pw *promWriter, now time.Time
 		}
 	}
 
+	if m := s.mailReport(); m != nil {
+		for _, r := range m.Results {
+			pw.gauge("jarl_mail_reverse_dns_ok", "1 when an address that sends or receives a public zone's mail has a PTR record that resolves back to it, at the last check (every 6 hours).", b2f(r.OK),
+				"zone", r.Zone, "address", r.Address)
+		}
+	}
+
 	if tokens, err := s.store.ListTokens(ctx, 0); err == nil {
 		for _, t := range tokens {
 			if t.ExpiresAt != nil && t.RevokedAt == nil {

internal/server/present.go

@@ -29,6 +29,12 @@ func (s *Server) presentZone(st *model.State, z *model.Zone, counts map[int64]re
 			}
 		}
 	}
+	if pf, ok := dnsname.PrefixFromReverse(z.Name); ok {
+		out.Prefix = pf.String()
+		if z.Type == model.ZonePrimary {
+			out.PTRMissing = len(engine.PTRFills(st, z.ViewID, z.Name, st.ZoneRecords(z.ID)))
+		}
+	}
 	for _, o := range st.LinkedWith(z) {
 		out.LinkedWith = append(out.LinkedWith, st.ViewName(o))
 		out.Links = append(out.Links, api.ZoneLink{ID: o.ID, View: st.ViewName(o)})
@@ -118,7 +124,7 @@ func presentOption(st *model.State, o *model.Option) api.Option {
 	if c, ok := catalog.Default().Lookup(scope, o.Name); ok {
 		out.Description, out.Status = c.Description, c.Status
 	}
-	if f := namedconf.FormatValue(o.Name, o.Value); f != o.Value {
+	if f := namedconf.FormatValueList(o.Name, o.Value, 3); f != o.Value {
 		out.Formatted = f
 	}
 	return out

internal/server/routes.go

@@ -114,6 +114,10 @@ func (s *Server) routes() {
 	m.HandleFunc("GET "+p+"/zones/{zone}/compare", s.authed(s.zoneCompare))
 	m.HandleFunc("POST "+p+"/zones/{zone}/link", s.authed(s.zoneLink(true)))
 	m.HandleFunc("POST "+p+"/zones/{zone}/unlink", s.authed(s.zoneLink(false)))
+	m.HandleFunc("POST "+p+"/zones/{zone}/fill-ptr", s.authed(s.zoneFillPTR))
+	m.HandleFunc("GET "+p+"/reverse-zones/suggestions", s.authed(s.reverseSuggestions))
+	m.HandleFunc("POST "+p+"/reverse-zones/dismiss", s.authed(s.reverseDismiss(true)))
+	m.HandleFunc("POST "+p+"/reverse-zones/undismiss", s.authed(s.reverseDismiss(false)))
 	m.HandleFunc("POST "+p+"/zones/{zone}/import", s.authed(s.importZoneFile))
 	m.HandleFunc("GET "+p+"/zones/{zone}/records", s.authed(s.listRecords))
 	m.HandleFunc("POST "+p+"/zones/{zone}/records", s.authed(s.createRecord))
@@ -129,6 +133,7 @@ func (s *Server) routes() {
 	m.HandleFunc("POST "+p+"/records/{id}/enable", s.authed(s.setRecordDisabled(false)))
 	// Options and settings
 	m.HandleFunc("GET "+p+"/options", s.authed(s.listOptions))
+	m.HandleFunc("GET "+p+"/options/generated", s.authed(s.generatedOptions))
 	m.HandleFunc("POST "+p+"/options", s.authed(s.createOption))
 	m.HandleFunc("GET "+p+"/options/{id}", s.authed(s.getOption))
 	m.HandleFunc("PATCH "+p+"/options/{id}", s.authed(s.updateOption))
@@ -180,6 +185,7 @@ func (s *Server) routes() {
 	m.HandleFunc("POST "+p+"/encrypted-dns/health", s.authed(s.encryptedDNSCheckNow))
 	m.HandleFunc("GET "+p+"/exposure", s.authed(s.exposure))
 	m.HandleFunc("POST "+p+"/exposure/fix", s.authed(s.exposureFix))
+	m.HandleFunc("POST "+p+"/exposure/mail", s.authed(s.mailCheckNow))
 	m.HandleFunc("POST "+p+"/exposure/ack", s.authed(s.exposureAck(true)))
 	m.HandleFunc("POST "+p+"/exposure/unack", s.authed(s.exposureAck(false)))
 	m.HandleFunc("GET "+p+"/stats/status", s.authed(s.statsStatus))

internal/server/server.go

@@ -24,6 +24,7 @@ import (
 	"jarl/internal/certs"
 	"jarl/internal/encdns"
 	"jarl/internal/engine"
+	"jarl/internal/mailcheck"
 	"jarl/internal/nscheck"
 	"jarl/internal/porkbun"
 	"jarl/internal/stats"
@@ -63,6 +64,12 @@ type Config struct {
 	TOTPIssuer  string
 	// Metrics configures /metrics (metrics.go).
 	Metrics Metrics
+	// RateLimitLog says rate limiting's log lines reach the statistics
+	// (stats.rate_limit_log), for the Exposure page.
+	RateLimitLog bool
+	// Resolvers are public recursive resolvers (acme.resolvers), to see
+	// the mail addresses' reverse DNS as receivers do.
+	Resolvers []string
 	// Certs manages TLS certificates (nil in tests that don't need it),
 	// including the one jarld serves (h_certs.go, sniff.go).
 	Certs *certs.Manager
@@ -99,6 +106,11 @@ type Server struct {
 		h *encdns.Health
 	}
 	encRoots *x509.CertPool
+	// mail is the last check of the mail addresses' reverse DNS (h_mail.go).
+	mail struct {
+		sync.Mutex
+		r *mailcheck.Report
+	}
 
 	mu   sync.Mutex
 	srvs []*http.Server
@@ -235,6 +247,7 @@ func (s *Server) Serve(ctx context.Context, ready func()) error {
 		ready()
 	}
 	go s.housekeeping(ctx)
+	go s.mailLoop(ctx)
 	go func() {
 		// Once jarld and named have settled after a start.
 		select {

internal/store/state.go

@@ -31,15 +31,15 @@ func loadState(ctx context.Context, e execer) (*model.State, error) {
 		}
 	}
 
-	rows, err := e.QueryContext(ctx, `SELECT id, name, position, match_clients, match_destinations, match_recursive_only, comment, exposure, acknowledged, version, created_at, updated_at, created_by, updated_by FROM views`)
+	rows, err := e.QueryContext(ctx, `SELECT id, name, position, match_clients, match_destinations, match_recursive_only, comment, exposure, acknowledged, reverse_suggestions_off, dismissed_reverse, version, created_at, updated_at, created_by, updated_by FROM views`)
 	if err != nil {
 		return nil, err
 	}
 	for rows.Next() {
 		v := &model.View{}
-		var mc, md, acks, ca, ua string
+		var mc, md, acks, dismissed, ca, ua string
 		var mro sql.NullInt64
-		if err := rows.Scan(&v.ID, &v.Name, &v.Position, &mc, &md, &mro, &v.Comment, &v.Exposure, &acks, &v.Version, &ca, &ua, &v.CreatedBy, &v.UpdatedBy); err != nil {
+		if err := rows.Scan(&v.ID, &v.Name, &v.Position, &mc, &md, &mro, &v.Comment, &v.Exposure, &acks, &v.ReverseSuggestionsOff, &dismissed, &v.Version, &ca, &ua, &v.CreatedBy, &v.UpdatedBy); err != nil {
 			rows.Close()
 			return nil, err
 		}
@@ -48,6 +48,9 @@ func loadState(ctx context.Context, e execer) (*model.State, error) {
 		if acks != "[]" && acks != "" {
 			json.Unmarshal([]byte(acks), &v.Acknowledged)
 		}
+		if dismissed != "[]" && dismissed != "" {
+			json.Unmarshal([]byte(dismissed), &v.DismissedReverse)
+		}
 		if mro.Valid {
 			v.MatchRecursiveOnly = model.Ptr(mro.Int64 != 0)
 		}
@@ -95,14 +98,14 @@ func loadState(ctx context.Context, e execer) (*model.State, error) {
 		return nil, err
 	}
 
-	rows, err = e.QueryContext(ctx, `SELECT id, name, view_id, type, in_view, file, soa_mname, soa_rname, soa_serial, soa_refresh, soa_retry, soa_expire, soa_minimum, default_ttl, serial_policy, dnssec_policy, comment, disabled, link_group, version, created_at, updated_at, created_by, updated_by FROM zones`)
+	rows, err = e.QueryContext(ctx, `SELECT id, name, view_id, type, in_view, file, soa_mname, soa_rname, soa_serial, soa_refresh, soa_retry, soa_expire, soa_minimum, default_ttl, serial_policy, dnssec_policy, comment, disabled, link_group, auto_ptr, version, created_at, updated_at, created_by, updated_by FROM zones`)
 	if err != nil {
 		return nil, err
 	}
 	for rows.Next() {
 		z := &model.Zone{}
 		var ca, ua string
-		if err := rows.Scan(&z.ID, &z.Name, &z.ViewID, &z.Type, &z.InView, &z.File, &z.SOA.MName, &z.SOA.RName, &z.SOA.Serial, &z.SOA.Refresh, &z.SOA.Retry, &z.SOA.Expire, &z.SOA.Minimum, &z.DefaultTTL, &z.SerialPolicy, &z.DNSSECPolicy, &z.Comment, &z.Disabled, &z.LinkGroup, &z.Version, &ca, &ua, &z.CreatedBy, &z.UpdatedBy); err != nil {
+		if err := rows.Scan(&z.ID, &z.Name, &z.ViewID, &z.Type, &z.InView, &z.File, &z.SOA.MName, &z.SOA.RName, &z.SOA.Serial, &z.SOA.Refresh, &z.SOA.Retry, &z.SOA.Expire, &z.SOA.Minimum, &z.DefaultTTL, &z.SerialPolicy, &z.DNSSECPolicy, &z.Comment, &z.Disabled, &z.LinkGroup, &z.AutoPTR, &z.Version, &ca, &ua, &z.CreatedBy, &z.UpdatedBy); err != nil {
 			rows.Close()
 			return nil, err
 		}
@@ -267,8 +270,8 @@ func saveState(ctx context.Context, e execer, old, new *model.State) error {
 		if v.MatchRecursiveOnly != nil {
 			mro = boolInt(*v.MatchRecursiveOnly)
 		}
-		_, err := e.ExecContext(ctx, `INSERT OR REPLACE INTO views (id, name, position, match_clients, match_destinations, match_recursive_only, comment, exposure, acknowledged, version, created_at, updated_at, created_by, updated_by) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?)`,
-			v.ID, v.Name, v.Position, jsonText(nonNil(v.MatchClients)), jsonText(nonNil(v.MatchDestinations)), mro, v.Comment, v.Exposure, jsonText(nonNilAcks(v.Acknowledged)), v.Version, ts(v.CreatedAt), ts(v.UpdatedAt), v.CreatedBy, v.UpdatedBy)
+		_, err := e.ExecContext(ctx, `INSERT OR REPLACE INTO views (id, name, position, match_clients, match_destinations, match_recursive_only, comment, exposure, acknowledged, reverse_suggestions_off, dismissed_reverse, version, created_at, updated_at, created_by, updated_by) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`,
+			v.ID, v.Name, v.Position, jsonText(nonNil(v.MatchClients)), jsonText(nonNil(v.MatchDestinations)), mro, v.Comment, v.Exposure, jsonText(nonNilAcks(v.Acknowledged)), v.ReverseSuggestionsOff, jsonText(nonNil(v.DismissedReverse)), v.Version, ts(v.CreatedAt), ts(v.UpdatedAt), v.CreatedBy, v.UpdatedBy)
 		return err
 	}, func(id int64) error { return del(ctx, e, "views", id) }); err != nil {
 		return err
@@ -288,8 +291,8 @@ func saveState(ctx context.Context, e execer, old, new *model.State) error {
 		return err
 	}
 	if err := diffMap(old.Zones, new.Zones, func(z *model.Zone) error {
-		_, err := e.ExecContext(ctx, `INSERT OR REPLACE INTO zones (id, name, view_id, type, in_view, file, soa_mname, soa_rname, soa_serial, soa_refresh, soa_retry, soa_expire, soa_minimum, default_ttl, serial_policy, dnssec_policy, comment, disabled, link_group, version, created_at, updated_at, created_by, updated_by) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`,
-			z.ID, z.Name, z.ViewID, z.Type, z.InView, z.File, z.SOA.MName, z.SOA.RName, z.SOA.Serial, z.SOA.Refresh, z.SOA.Retry, z.SOA.Expire, z.SOA.Minimum, z.DefaultTTL, z.SerialPolicy, z.DNSSECPolicy, z.Comment, z.Disabled, z.LinkGroup, z.Version, ts(z.CreatedAt), ts(z.UpdatedAt), z.CreatedBy, z.UpdatedBy)
+		_, err := e.ExecContext(ctx, `INSERT OR REPLACE INTO zones (id, name, view_id, type, in_view, file, soa_mname, soa_rname, soa_serial, soa_refresh, soa_retry, soa_expire, soa_minimum, default_ttl, serial_policy, dnssec_policy, comment, disabled, link_group, auto_ptr, version, created_at, updated_at, created_by, updated_by) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`,
+			z.ID, z.Name, z.ViewID, z.Type, z.InView, z.File, z.SOA.MName, z.SOA.RName, z.SOA.Serial, z.SOA.Refresh, z.SOA.Retry, z.SOA.Expire, z.SOA.Minimum, z.DefaultTTL, z.SerialPolicy, z.DNSSECPolicy, z.Comment, z.Disabled, z.LinkGroup, z.AutoPTR, z.Version, ts(z.CreatedAt), ts(z.UpdatedAt), z.CreatedBy, z.UpdatedBy)
 		return err
 	}, func(id int64) error { return del(ctx, e, "zones", id) }); err != nil {
 		return err

internal/store/store.go

@@ -366,6 +366,15 @@ CREATE TABLE certificates (
 	`
 ALTER TABLE zones ADD COLUMN link_group INTEGER NOT NULL DEFAULT 0;
 ALTER TABLE records ADD COLUMN shared_id INTEGER NOT NULL DEFAULT 0;
+`,
+	// 12: PTR records kept in step per zone (docs/reverse.md).
+	`
+ALTER TABLE zones ADD COLUMN auto_ptr INTEGER NOT NULL DEFAULT 0;
+`,
+	// 13: reverse zone suggestions per view (docs/reverse.md).
+	`
+ALTER TABLE views ADD COLUMN reverse_suggestions_off INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE views ADD COLUMN dismissed_reverse TEXT NOT NULL DEFAULT '[]';
 `,
 }
 

internal/web/static/assets/names.js

@@ -182,3 +182,17 @@ export function checkDomain(input) {
   if (isReverseZone(name)) notes.push("a reverse zone: choosing \"Reverse zone\" and giving the network is easier");
   return { name, problems, notes };
 }
+
+// maskNetwork returns the network of the given size an address (or a
+// network, "2a02:8013:7f3d:10::/64") is in: maskNetwork("2a02:8013:7f3d:10::5", 48)
+// is "2a02:8013:7f3d::/48". null when it isn't an address.
+export function maskNetwork(input, bits) {
+  const addr = String(input).trim().split("/")[0];
+  const b4 = parseIPv4(addr);
+  const n6 = b4 ? null : parseIPv6(addr);
+  if (!b4 && !n6) return null;
+  const digits = b4 || n6.map((x) => parseInt(x, 16));
+  const step = b4 ? 8 : 4;
+  const net = digits.map((d, i) => { const k = Math.max(0, Math.min(step, bits - i * step)); return d & ~((1 << (step - k)) - 1) & ((1 << step) - 1); });
+  return (b4 ? net.join(".") : sixOf(net.map((d) => d.toString(16)))) + "/" + bits;
+}

internal/web/static/assets/pages/exposure.js

@@ -1,8 +1,8 @@
 // Internet exposure (docs/exposure.md): which views are reachable from
 // the internet, why, and what to harden, with fixes staged like any edit
 // and findings that can be accepted on purpose.
-import { h, mount, table, toast, badge, modal, input, field, errorBox, select, plural } from "../ui.js";
-import { get, change, describeResult, can } from "../api.js";
+import { h, mount, table, toast, badge, modal, input, field, errorBox, select, plural, relTime } from "../ui.js";
+import { api, get, change, describeResult, can } from "../api.js";
 import { rerender } from "../app.js";
 
 const sevKind = { warning: "warn", error: "err", info: "" };
@@ -28,7 +28,11 @@ export async function render(el) {
   parts.push(h("div", { class: "panel" }, h("h2", null, "Findings ", badge(plural(all.filter((f) => f.severity === "warning").length, "warning"), all.some((f) => f.severity === "warning") ? "warn" : "ok")),
     all.length ? h("div", { class: "findings" }, all.map((f) => findingRow(f, writable))) : h("div", { class: "empty" }, r.scopes.some((s) => s.public) ? "Nothing to harden." : "No view is reachable from the internet, so there is nothing to check.")));
 
-  if (r.rate_limiting) parts.push(activity(r.rate_limiting, r.scopes));
+  if (r.rate_limiting && r.rate_limit_log) parts.push(activity(r.rate_limiting, r.scopes));
+  else if (r.rate_limiting && r.scopes.some((s) => s.public && s.rate_limit !== "off")) {
+    parts.push(h("div", { class: "msg info" }, "What rate limiting limits isn't counted: stats.rate_limit_log is off in /etc/jarl/jarl.yaml, so its log lines stay in named's syslog only."));
+  }
+  if (r.scopes.some((s) => s.public)) parts.push(mailPanel(r.mail));
   mount(el, parts);
 }
 
@@ -118,3 +122,31 @@ function activity(a, scopes) {
         table([{ label: "Client network (limited or would be)", render: (e) => h("span", { class: "mono" }, e.key) }, { label: "Responses", render: (e) => String(e.count) }], a.networks || []),
         table([{ label: "Name and type", render: (e) => h("span", { class: "mono" }, e.key) }, { label: "Responses", render: (e) => String(e.count) }], a.names || []))]);
 }
+
+// mailPanel: the reverse DNS of the addresses that send and receive the
+// public zones' mail, as receivers check it (docs/exposure.md#mail).
+function mailPanel(m) {
+  const out = h("div");
+  const lv = { ok: "ok", info: "", warning: "warn" };
+  const draw = (x) => {
+    if (!x) return mount(out, h("div", { class: "muted" }, "Not checked yet: Jarl checks a minute after it starts, then every 6 hours."));
+    const rows = x.results.length ? table([
+      { label: "Address", render: (r) => [h("span", { class: "mono" }, r.address), h("div", { class: "muted small" }, r.zone + ": " + r.roles.join(", "))] },
+      { label: "PTR", render: (r) => r.ptr.length ? h("span", { class: "mono" }, r.ptr.join(", ")) : h("span", { class: "muted" }, "none") },
+      { label: "Reverse zone run by", render: (r) => h("span", { class: "small" }, r.managed_by || "–") },
+      { label: "", render: (r) => [badge(r.ok ? (r.level === "info" ? "works, note" : "works") : "problem", lv[r.level]),
+        r.level !== "ok" ? h("div", { class: "small" }, r.message) : null,
+        r.local_zone ? h("div", { class: "muted small" }, "Jarl's reverse zone " + r.local_zone + " only answers your own clients: receivers ask " + (r.managed_by || "the address's owner") + ".") : null] },
+    ], x.results) : h("div", { class: "empty" }, "No public zone has an MX record or SPF addresses.");
+    mount(out, rows, (x.errors || []).map((e) => h("div", { class: "msg err small" }, e)),
+      h("div", { class: "muted small" }, "Checked ", relTime(x.checked), "."));
+  };
+  draw(m);
+  const btn = h("button", { class: "small", onclick: async () => {
+    btn.disabled = true;
+    try { draw(await api("POST", "/exposure/mail", { body: {} })); } catch (e) { toast(e.message, "err", 8000); } finally { btn.disabled = false; }
+  } }, "Check now");
+  return h("div", { class: "panel" }, h("div", { class: "page-head" }, h("h2", { class: "grow" }, "Mail reverse DNS"), h("div", { class: "actions" }, btn)),
+    h("p", { class: "muted small" }, "Receivers such as Gmail and Outlook reject or mark mail from an address without a PTR record whose name resolves back to it. These records belong to whoever owns the address (your hosting provider or ISP), so Jarl looks them up as the internet sees them: the addresses of your public zones' MX hosts and SPF records."),
+    out);
+}

internal/web/static/assets/pages/options.js

@@ -159,14 +159,32 @@ export async function render(el) {
   const settingsEl = h("div");
   const serverEl = h("div");
   const topEl = h("div");
+  const genEl = h("div");
   mount(el,
     h("div", { class: "page-head" }, h("div", { class: "grow" }, h("h1", null, "Server options"),
       h("div", { class: "muted" }, "Global named options, top-level statements such as logging and controls, and Jarl's defaults for new zones."))),
-    settingsEl, serverEl, topEl);
+    settingsEl, serverEl, topEl, genEl);
   settingsForm(settingsEl, settings);
   await optionsEditor(serverEl, { scope: "options", catalogScope: "options", title: "options { }", intro: "These apply to the whole server; views and zones can override many of them." });
   await optionsEditor(topEl, { scope: "toplevel", catalogScope: "toplevel", title: "Top-level statements",
     intro: "Statements outside options { }, such as logging, controls, statistics-channels, server, remote-servers, tls or include. Values are named.conf syntax, e.g. { channel ... ; category ... ; } for logging." });
+  generatedPanel(genEl, await get("/options/generated").catch(() => []));
+}
+
+// generatedPanel lists what Jarl adds to named.conf by itself: read-only,
+// with why and what turns it on or off.
+function generatedPanel(el, list) {
+  if (!list.length) return;
+  mount(el, h("div", { class: "panel" },
+    h("h2", null, "Added by Jarl"),
+    h("p", { class: "muted" }, "Jarl writes these into named.conf itself, for its own features. They aren't options you can edit here: each is controlled by the setting shown."),
+    h("div", { class: "table-wrap" }, h("table", null,
+      h("thead", null, h("tr", null, h("th", null, "Where"), h("th", null, "Statement"), h("th", null, "Why"), h("th", null, "Controlled by"))),
+      h("tbody", null, list.map((g) => h("tr", null,
+        h("td", { class: "small" }, g.where),
+        h("td", null, h("pre", { class: "code optval wrap" }, g.text)),
+        h("td", { class: "small" }, g.why),
+        h("td", { class: "small mono" }, g.setting))))))));
 }
 
 function settingsForm(el, s) {

internal/web/static/assets/pages/views.js

@@ -125,6 +125,7 @@ async function viewForm(v, viewless) {
   const mro = select([["", "(default: no)"], ["true", "yes"], ["false", "no"]], v && v.match_recursive_only !== undefined && v.match_recursive_only !== null ? String(v.match_recursive_only) : "");
   const comment = input({ value: v ? v.comment : "" });
   const color = colorPicker(v ? v.color : "");
+  const revSuggest = checkbox("Suggest reverse zones for the addresses this view's records use", !(v && v.reverse_suggestions_off));
   const adopt = checkbox("Move the " + viewless.length + " zone(s) that are not in a view into this view", true);
   const body = h("div", null, h("div", { class: "form-grid" },
     field("Name", name),
@@ -132,6 +133,7 @@ async function viewForm(v, viewless) {
     field("Match destinations", h("div", null, md, suggestions(md, ctx)), "Server addresses this view answers on (optional)."),
     field("Recursive only", mro, "If yes, only recursive queries match this view."),
     field("Comment", comment),
+    field("Reverse zones", revSuggest, "Turn it off for a view only some servers use (a VPS's view, say): its addresses then get no suggestions under Zones, and it doesn't count when Jarl picks the view of a new reverse zone. Public views never get suggestions."),
     field("Colour", color, "How the web UI shows this view, so zones of the same view are easy to spot. Only changes the web UI: it applies at once, with no deploy.")),
     !v && viewless.length ? h("div", { class: "msg warn" }, "Once views exist, named requires every zone to be inside a view. ", adopt) : null,
     err);
@@ -139,6 +141,7 @@ async function viewForm(v, viewless) {
     mount(err);
     const data = { name: name.value.trim(), match_clients: lines(mc.value), match_destinations: lines(md.value), comment: comment.value };
     data.match_recursive_only = mro.value === "" ? null : mro.value === "true";
+    data.reverse_suggestions = revSuggest.input.checked;
     if (!v && viewless.length && adopt.input.checked) data.adopt_zones = true;
     const colorChanged = color.value !== ((v && v.color) || "");
     try {
@@ -170,7 +173,7 @@ function configChanged(v, data) {
   const same = (a, b) => JSON.stringify(a || []) === JSON.stringify(b || []);
   const mro = v.match_recursive_only === undefined ? null : v.match_recursive_only;
   return data.name !== v.name || !same(data.match_clients, v.match_clients) || !same(data.match_destinations, v.match_destinations) ||
-    data.match_recursive_only !== mro || data.comment !== (v.comment || "");
+    data.match_recursive_only !== mro || data.comment !== (v.comment || "") || data.reverse_suggestions === !!v.reverse_suggestions_off;
 }
 
 async function deleteView(v) {

internal/web/static/assets/pages/zone.js

@@ -1,5 +1,5 @@
-import { h, mount, table, field, input, select, textarea, toast, errorBox, display, badge, confirmDialog, modal, checkbox, time, diffView, backLink, viewLink, lastList } from "../ui.js";
-import { api, get, stream, change, describeResult, rrtypes, state, draftQuery } from "../api.js";
+import { h, mount, table, field, input, select, textarea, toast, errorBox, display, badge, confirmDialog, modal, checkbox, time, diffView, backLink, viewLink, lastList, plural } from "../ui.js";
+import { api, get, stream, change, changeMany, describeResult, rrtypes, state, draftQuery, can } from "../api.js";
 import { rerender } from "../app.js";
 import { optionsEditor } from "./options.js";
 import { emailOf, pendingBadge } from "./zones.js";
@@ -34,6 +34,8 @@ export async function render(el, params, query) {
           zone.pending ? [pendingBadge(zone.pending), " "] : null,
           zone.view ? ["view ", viewLink(view, zone.view, "#/zones/" + id + (params.tab ? "/" + params.tab : "")), " · "] : null,
           zone.type === "primary" ? "serial " + zone.soa.serial + " · " : null,
+          zone.prefix ? h("span", { class: "mono" }, zone.prefix + " · ") : null,
+          zone.auto_ptr ? [h("a", { href: "#/zones/" + id + "/settings", title: "Adding, changing, disabling or deleting an A or AAAA record does the same to its PTR record" }, badge("PTRs kept in step", "ok")), " "] : null,
           zone.dnssec_policy ? [h("a", { href: "#/zones/" + id + "/dnssec" }, badge(zone.dnssec_policy === "insecure" ? "DNSSEC: turning off" : "DNSSEC", zone.dnssec_policy === "insecure" ? "warn" : "ok")), " "] : null,
           zone.links ? [h("span", { class: "badge accent" }, "linked with ",
             zone.links.map((l, i) => [i ? ", " : "", h("a", { href: "#/zones/" + l.id + (params.tab ? "/" + params.tab : ""), title: "The zone in view " + l.view }, l.view)])), " "] : null,
@@ -46,7 +48,10 @@ export async function render(el, params, query) {
         zone.type === "primary" && zone.view ? [linkButton(zone), " "] : null,
         h("button", { class: "danger", onclick: () => deleteZone(zone) }, "Delete zone")));
   const banner = zone.disabled ? h("div", { class: "msg warn" },
-    h("strong", null, "This zone is disabled: "), "named doesn't load it. It is kept here, with its records, and can still be edited; enabling it serves it as it is then.") : null;
+    h("strong", null, "This zone is disabled: "), "named doesn't load it. It is kept here, with its records, and can still be edited; enabling it serves it as it is then.")
+    : zone.ptr_missing && can("zones", true) ? h("div", { class: "msg info" },
+      plural(zone.ptr_missing, "address", "addresses") + " in " + zone.prefix + " that " + (zone.view ? "view " + zone.view + "'s" : "your") + " A and AAAA records use " + (zone.ptr_missing === 1 ? "has" : "have") + " no PTR record here. ",
+      h("button", { class: "small", onclick: () => fillPTR(zone) }, "Add " + (zone.ptr_missing === 1 ? "it" : "them"))) : null;
   const tabBar = h("div", { class: "tabs" }, tabs.map(([k, label]) => h("a", { href: "#/zones/" + id + "/" + k, class: k === tab ? "active" : "" }, label)));
   // The header and tabs show at once. Below them, switching tabs keeps the
   // previous tab's content (faded) until the new one is loaded, rather
@@ -65,7 +70,7 @@ export async function render(el, params, query) {
   else if (tab === "servers") await serversTab(body, zone);
   else if (tab === "dnssec") await dnssecTab(body, zone);
   else if (tab === "registrar") await registrarTab(body, zone);
-  else if (tab === "compare") await compareTab(body, zone);
+  else if (tab === "compare") await compareTab(body, zone, query);
   // A later click (another tab) has taken over the page.
   if (seq !== renderSeq || !holder.isConnected) return;
   holder.replaceWith(body);
@@ -77,34 +82,110 @@ export async function render(el, params, query) {
 
 // compareTab shows the names and types that differ between the views that
 // have the zone, with a button to share one view's version (linked zones).
-async function compareTab(el, zone) {
-  let all = false;
+// compareTab compares the zone with the same zone in other views, from
+// this one (docs/views.md#comparing-views): a summary, what the views
+// answer differently, the names only some views have, and how much is
+// the same. ?name= (and &type=) narrows it to one name.
+async function compareTab(el, zone, query) {
+  const others = zone.other_views || [];
+  const withSel = select([...(others.length > 1 ? [["", "all other views"]] : []), ...others.map((v) => [v, v])], query.get("with") || others[0] || "");
+  const nameIn = input({ value: query.get("name") || "", placeholder: "all names, or one: www, @", class: "mono", style: { width: "200px" } });
+  const typeIn = input({ value: query.get("type") || "", placeholder: "any type", class: "mono", style: { width: "90px" } });
+  let showSame = false;
   const out = h("div");
+  const one = (d) => h("div", { class: "oneline mono small", title: d }, d);
   const draw = async () => {
-    const r = await get("/zones/" + zone.id + "/compare", { all: all ? 1 : "" });
-    const head = h("tr", null, h("th", null, "Name"), h("th", null, "Type"), r.views.map((v) => h("th", null, v)));
-    const rows = r.rows.map((row) => h("tr", { class: row.same ? "muted" : "" },
-      h("td", { class: "mono" }, row.name), h("td", null, h("strong", null, row.type)),
-      row.views.map((vs) => h("td", { class: "compare-cell" },
-        vs.records.length ? vs.records.map((d) => h("div", { class: "mono small" }, d)) : h("span", { class: "muted" }, "–"),
-        vs.linked === "local" ? [badge("only " + vs.view, "accent"), " "] : null,
-        r.linked && !row.same && vs.records.length ? h("button", { class: "small", title: "Make view " + vs.view + "'s version every view's: the others' records of this name and type are replaced",
-          onclick: () => share(vs, row) }, "Use this version") : null))));
-    mount(out,
-      h("p", { class: "muted" }, r.same + " names and types are the same in " + r.views.join(", ") + (r.rows.length && !all ? "; these differ." : ".") + " ",
-        r.linked ? "The zones are linked: shared records are kept in step, and a view's own records override them there." : "The zones aren't linked: a change in one doesn't reach the others. Link them (Link… above) to keep what is the same in step; linking changes no answer."),
-      r.rows.length ? h("div", { class: "table-wrap" }, h("table", { class: "compare" }, h("thead", null, head), h("tbody", null, rows))) : h("div", { class: "empty" }, "Nothing differs."),
-      h("label", { class: "check" }, h("input", { type: "checkbox", checked: all, onchange: (e) => { all = e.target.checked; draw(); } }), "Show what is the same too"));
+    const q = { with: withSel.value || undefined, name: nameIn.value.trim() || undefined, type: nameIn.value.trim() ? typeIn.value.trim() || undefined : undefined, all: showSame ? 1 : undefined };
+    let r;
+    try { r = await get("/zones/" + zone.id + "/compare", draftQuery(q)); } catch (e) { mount(out, errorBox(e)); return; }
+    const oneName = !!q.name;
+    const parts = [];
+    parts.push(h("p", { class: "muted" }, r.linked
+      ? "The zones are linked: shared records are kept in step, so a difference is a view's own records, there on purpose."
+      : "The zones aren't linked: nothing keeps them in step, so a difference may be one that crept in. Link them (Link… above) to keep what is the same in step."));
+    if (!oneName) parts.push(h("ul", { class: "compare-summary" }, r.summary.map((s) => h("li", null,
+      h("strong", null, s.view), ": ",
+      [[s.different, "answered differently"], [s.only_base, "only in " + r.base], [s.only_other, "only in " + s.view], [s.same, "the same"]]
+        .map(([n, what], i) => [i ? " · " : "", h("span", { class: n && i < 3 ? "" : "muted" }, n + " " + what)])))));
+
+    if (r.different.length) {
+      parts.push(h("h3", null, "Answered differently (" + r.different.length + ")"),
+        h("div", { class: "table-wrap" }, h("table", { class: "compare" },
+          h("thead", null, h("tr", null, h("th", null, "Name"), h("th", null, "Type"), r.views.map((v) => h("th", null, v)))),
+          h("tbody", null, r.different.map((row) => h("tr", null,
+            h("td", { class: "mono" }, row.name), h("td", null, h("strong", null, row.type)),
+            row.views.map((vs) => h("td", { class: "compare-cell" },
+              vs.records.length ? vs.records.map(one) : h("span", { class: "muted" }, "–"),
+              vs.records.length ? h("div", { class: "compare-actions" },
+                vs.linked === "local" ? [badge("own records", "accent"), " "] : null,
+                h("button", { class: "small", title: "Every view gets " + vs.view + "'s records for " + row.name + " " + row.type, onclick: () => useEverywhere(r, row, vs) }, "Use this everywhere")) : null))))))));
+    }
+    for (const o of r.only) {
+      const missing = r.views.filter((v) => !o.views.includes(v));
+      parts.push(h("details", { class: "compare-only", open: oneName || o.rows.length <= 8 },
+        h("summary", null, h("strong", null, "Only in " + o.views.join(" and ")), " (" + o.rows.length + ")",
+          h("span", { class: "muted small" }, " · " + missing.join(", ") + (missing.length > 1 ? " have" : " has") + " no records of these names and types")),
+        h("div", { class: "table-wrap" }, h("table", { class: "compare" }, h("tbody", null, o.rows.map((row) => {
+          const src = row.views.find((vs) => vs.records.length);
+          return h("tr", null, h("td", { class: "mono" }, row.name), h("td", null, h("strong", null, row.type)),
+            h("td", { class: "compare-cell" }, src.records.map(one)),
+            h("td", { class: "actions-cell" }, missing.map((v) => h("button", { class: "small", title: "Give view " + v + " the same records (its own, local to it)", onclick: () => copyTo(row, src, row.views.find((x) => x.view === v)) }, "Add to " + v))));
+        }))))));
+    }
+    if (r.same_rows && r.same_rows.length) {
+      parts.push(h("h3", null, "The same in " + r.views.join(", ") + " (" + r.same_rows.length + ")"),
+        h("div", { class: "table-wrap" }, h("table", { class: "compare" }, h("tbody", null, r.same_rows.map((row) => h("tr", { class: "muted" },
+          h("td", { class: "mono" }, row.name), h("td", null, row.type), h("td", { class: "compare-cell" }, row.views[0].records.map(one))))))));
+    } else if (!oneName && r.same) {
+      parts.push(h("p", { class: "muted" }, r.same + " names and types are the same. ", h("a", { href: "#", onclick: (e) => { e.preventDefault(); showSame = true; draw(); } }, "List them")));
+    }
+    if (oneName && !r.different.length && !r.only.length && !(r.same_rows || []).length) parts.push(h("div", { class: "empty" }, "No records of that name in these views."));
+    else if (!r.different.length && !r.only.length && !oneName) parts.push(h("div", { class: "empty" }, "Nothing differs."));
+    mount(out, parts);
   };
-  const share = async (vs, row) => {
-    if (!await confirmDialog("Use view " + vs.view + "'s " + row.name + " " + row.type, "Every view gets " + vs.records.join(", ") + " for " + row.name + " " + row.type + ", shared from now on; the other views' records of that name and type are replaced.", "Use this version")) return;
+  // useEverywhere gives every view one view's records of a name and type:
+  // in a linked zone by sharing them, otherwise by setting each zone's.
+  const useEverywhere = async (r, row, vs) => {
+    const rest = row.views.filter((x) => x !== vs);
+    const linkedAll = r.linked && zone.linked_with;
+    const msg = linkedAll
+      ? "View " + vs.view + "'s " + row.name + " " + row.type + " records become shared: every linked view (" + [zone.view, ...zone.linked_with].join(", ") + ") answers " + vs.data.join(", ") + ", and their own records of that name and type are replaced."
+      : rest.map((x) => x.view).join(" and ") + " get" + (rest.length > 1 ? "" : "s") + " " + vs.data.join(", ") + " for " + row.name + " " + row.type + ", replacing what " + (rest.length > 1 ? "they have" : "it has") + ".";
+    if (!await confirmDialog("Use " + vs.view + "'s " + row.name + " " + row.type, msg, "Use this everywhere")) return;
     try {
-      toast(describeResult(await change("PATCH", "/records/" + vs.ids[0], { local: false })));
+      const res = linkedAll
+        ? await change("PATCH", "/records/" + vs.ids[0], { local: false })
+        : await changeMany(rest.map((x) => ({ op: "rrset.replace", data: rrsetFrom(row, vs, x) })), "use " + vs.view + "'s " + row.name + " " + row.type);
+      toast(describeResult(res));
       await draw();
     } catch (e) { toast(e.message, "err", 8000); }
   };
+  const copyTo = async (row, src, dst) => {
+    try {
+      toast(describeResult(await changeMany([{ op: "rrset.replace", data: rrsetFrom(row, src, dst) }], "add " + row.name + " " + row.type + " to view " + dst.view)));
+      await draw();
+    } catch (e) { toast(e.message, "err", 8000); }
+  };
+  const go = () => draw();
+  withSel.addEventListener("change", go);
+  nameIn.addEventListener("keydown", (e) => { if (e.key === "Enter") go(); });
+  typeIn.addEventListener("keydown", (e) => { if (e.key === "Enter") go(); });
+  mount(el, h("div", { class: "panel" },
+    h("div", { class: "compare-controls" },
+      h("label", null, "Compare " + zone.view + " with "), withSel, " ",
+      h("label", null, " Name "), nameIn, typeIn, " ",
+      h("button", { class: "small", onclick: go }, "Compare"),
+      nameIn.value ? [" ", h("button", { class: "small", onclick: () => { nameIn.value = ""; typeIn.value = ""; go(); } }, "All names")] : null),
+    out));
   await draw();
-  mount(el, out);
+}
+
+// rrsetFrom is the request giving zone dst a name and type's records from
+// src: its own (local) records, in a linked zone.
+function rrsetFrom(row, src, dst) {
+  const d = { zone_id: dst.zone_id, name: row.fqdn, type: row.type, data: src.data, local: true };
+  if (src.ttl !== undefined && src.ttl !== null) d.ttl = src.ttl;
+  return d;
 }
 
 // ---- linked zones (docs/views.md#linked-zones)
@@ -442,7 +523,7 @@ async function recordsTab(el, zone, query) {
     const t = typeInfo[fType.value] || {};
     fData.placeholder = reverse && fType.value === "PTR" ? "nas.adbraun.lol" : t.example || t.format || "";
     mount(hint, h("strong", null, fType.value + ": "), t.description || "", t.format ? [" · format: ", h("code", null, t.format)] : null);
-    fPTR.classList.toggle("hidden", !(fType.value === "A" || fType.value === "AAAA"));
+    fPTR.classList.toggle("hidden", zone.auto_ptr || !(fType.value === "A" || fType.value === "AAAA"));
   };
   fType.addEventListener("change", () => { showHint(); preview(); });
   showHint();
@@ -605,6 +686,7 @@ async function recordsTab(el, zone, query) {
           : h("button", { class: "small reveal", title: "Make " + r.relative_name + " " + r.type + " this view's own, so it can differ here; the other views keep the shared one", onclick: () => setLocal(r, true) }, "Only here"), " "] : null,
         !reverse && (r.type === "A" || r.type === "AAAA") && !r.disabled
           ? [h("button", { class: "small reveal", title: "Add a CNAME record that points to " + r.name.replace(/\.$/, ""), onclick: () => aliasTo(r) }, "+ CNAME"), " "] : null,
+        zone.other_views && !(r.type === "NS" && r.relative_name === "@") ? [h("a", { class: "button small reveal", href: "#/zones/" + zone.id + "/compare?name=" + encodeURIComponent(r.relative_name) + "&type=" + r.type, title: "Compare " + r.relative_name + " " + r.type + " with view" + (zone.other_views.length > 1 ? "s " : " ") + zone.other_views.join(", ") }, "Compare"), " "] : null,
         h("button", { class: "small", title: "Edit", onclick: () => edit(r) }, "Edit"), " ",
         r.disabled
           ? h("button", { class: "small toggle", title: "Put the record back in the zone", onclick: () => toggle(r) }, "Enable")
@@ -622,7 +704,9 @@ async function recordsTab(el, zone, query) {
   const del = async (r) => {
     const isAddr = r.type === "A" || r.type === "AAAA";
     let ptr = false;
-    if (isAddr) {
+    if (isAddr && zone.auto_ptr) {
+      if (!(await confirmDialog("Delete record", display(r.name) + " " + r.type + " " + r.data + ", and its PTR record (this zone keeps them in step)", "Delete", "danger"))) return;
+    } else if (isAddr) {
       const c = checkbox("Also delete the matching PTR record", true);
       const ok = await modal("Delete record", h("div", null, h("p", { class: "mono" }, display(r.name) + " " + r.type + " " + r.data), c), [{ label: "Cancel", value: false }, { label: "Delete", kind: "danger", value: true }]);
       if (ok !== true) return;
@@ -693,7 +777,7 @@ async function recordsTab(el, zone, query) {
         h("div", { class: "f" }, h("label", null, "TTL"), eTTL),
         h("div", { class: "f grow" }, h("label", null, "Data"), eData),
         h("div", { class: "f" }, h("label", null, "Comment"), eComment),
-        (r.type === "A" || r.type === "AAAA") ? h("div", { class: "f" }, h("label", null, " "), ePTR) : null,
+        (r.type === "A" || r.type === "AAAA") && !zone.auto_ptr ? h("div", { class: "f" }, h("label", null, " "), ePTR) : null,
         h("div", { class: "f" }, h("label", null, " "), h("span", null, h("button", { class: "primary", onclick: save }, "Save"), " ", h("button", { onclick: () => { editing = null; draw(); } }, "Cancel")))),
       h("div", { class: "hint" }, "Created ", time(r.created_at), r.created_by ? " by " + r.created_by : "", "; changed ", time(r.updated_at), r.updated_by ? " by " + r.updated_by : "", "."),
       eErr);
@@ -733,6 +817,7 @@ async function settingsTab(el, zone) {
   const view = select([["", "(no view)"], ...views.map((v) => [String(v.id), v.name])], String(zone.view_id || ""));
   const file = input({ value: zone.file || "", class: "mono" });
   const comment = textarea(zone.comment, { rows: 2 });
+  const autoPTR = checkbox("Keep PTR records in step with the A and AAAA records", !!zone.auto_ptr);
   if (zone.type === "primary") {
     rows.push(
       field("Primary name server", mname, "SOA MNAME."),
@@ -743,6 +828,8 @@ async function settingsTab(el, zone) {
       field("Negative TTL", minimum, "SOA minimum: how long resolvers cache 'does not exist' answers (at most 3 hours in BIND)."),
       field("Default TTL", ttl, "TTL for records that don't set their own."),
       field("Serial policy", policy, "How the serial (now " + s.serial + ") is bumped when the zone changes."));
+    if (!zone.prefix && !/\.(in-addr|ip6)\.arpa\.$/.test(zone.name)) rows.push(field("Reverse DNS", autoPTR,
+      "Adding, changing, disabling or deleting an address record does the same to its PTR record, in the reverse zones of " + (zone.view ? "view " + zone.view + (zone.linked_with ? " and the linked views" : "") : "the server") + ". An address keeps the name it has; one without a reverse zone is left alone (Zones lists the reverse zones you're missing)."));
   }
   if (["secondary", "mirror", "stub", "hint", "redirect"].includes(zone.type)) rows.push(field("File", file, "Leave empty for a file managed by Jarl's cache directory (secondary zones)."));
   if (views.length) rows.push(field("View", view, "Moving a zone to another view changes which clients see it."));
@@ -754,6 +841,7 @@ async function settingsTab(el, zone) {
       body.soa = { mname: mname.value.trim(), rname: rname.value.trim(), refresh: +refresh.value, retry: +retry.value, expire: +expire.value, minimum: +minimum.value };
       body.default_ttl = +ttl.value;
       body.serial_policy = policy.value;
+      if (!!zone.auto_ptr !== autoPTR.input.checked) body.auto_ptr = autoPTR.input.checked;
     }
     if (["secondary", "mirror", "stub", "hint", "redirect"].includes(zone.type)) body.file = file.value.trim();
     if (views.length) body.view_id = view.value ? Number(view.value) : 0;
@@ -824,3 +912,13 @@ async function toggleZone(zone) {
     rerender();
   } catch (e) { toast(e.message, "err", 8000); }
 }
+
+// fillPTR adds the PTR records a reverse zone lacks (docs/reverse.md).
+async function fillPTR(zone) {
+  try {
+    const r = await change("POST", "/zones/" + zone.id + "/fill-ptr");
+    toast(describeResult(r));
+    (r.warnings || []).forEach((w) => toast(w, "warn", 10000));
+    rerender();
+  } catch (e) { toast(e.message, "err", 8000); }
+}

internal/web/static/assets/pages/zones.js

@@ -1,10 +1,11 @@
-import { h, mount, table, modal, field, input, select, textarea, lines, toast, errorBox, display, badge, viewLink, lastList, checkbox } from "../ui.js";
+import { h, mount, table, modal, field, input, select, textarea, lines, toast, errorBox, display, badge, viewLink, lastList, checkbox, plural, confirmDialog } from "../ui.js";
 import { get, change, changeMany, describeResult, can, draftQuery } from "../api.js";
 import { rerender } from "../app.js";
-import { checkDomain, reverseZoneFor } from "../names.js";
+import { checkDomain, reverseZoneFor, maskNetwork } from "../names.js";
 
 export async function render(el, params, query) {
-  const [zones, views, settings] = await Promise.all([get("/zones", draftQuery()), get("/views"), get("/settings")]);
+  const [zones, views, settings, suggestions] = await Promise.all([get("/zones", draftQuery()), get("/views"), get("/settings"),
+    get("/reverse-zones/suggestions", draftQuery()).catch(() => [])]);
   const filter = input({ type: "search", placeholder: "Filter zones…", value: query.get("q") || "" });
   const viewSel = select([["", "All views"], ...views.map((v) => [v.name, v.name])], query.get("view") || "");
   const typeSel = select([["", "All types"], "primary", "secondary", "forward", "stub", "static-stub", "mirror", "hint", "redirect", "in-view"], query.get("type") || "");
@@ -23,7 +24,7 @@ export async function render(el, params, query) {
     lastList.zones = hash;
     const rows = zones.filter((z) => (!q || z.name.includes(q)) && (!viewSel.value || z.view === viewSel.value) && (!typeSel.value || z.type === typeSel.value));
     mount(list, table([
-      { label: "Zone", render: (z) => [z.pending === "delete" ? h("span", null, z.display_name) : h("a", { href: "#/zones/" + z.id }, z.display_name), dnssecLock(z), z.disabled ? [" ", badge("disabled", "off")] : null, z.pending ? [" ", pendingBadge(z.pending)] : null], tdClass: "name" },
+      { label: "Zone", render: (z) => [z.pending === "delete" ? h("span", null, z.display_name) : h("a", { href: "#/zones/" + z.id }, z.display_name), z.prefix ? h("span", { class: "muted small" }, " " + z.prefix) : null, z.ptr_missing ? [" ", badge(z.ptr_missing + " PTR missing", "warn")] : null, dnssecLock(z), z.disabled ? [" ", badge("disabled", "off")] : null, z.pending ? [" ", pendingBadge(z.pending)] : null], tdClass: "name" },
       views.length ? { label: "View", render: (z) => viewLink(viewsById.get(z.view_id), z.view, hash) } : null,
       { label: "Type", render: (z) => badge(z.type, z.type === "primary" ? "accent" : "") },
       { label: "Records", render: (z) => z.type === "primary" ? [String(z.record_count), z.disabled_count ? h("span", { class: "muted small", title: z.disabled_count + " disabled (left out of the zone)" }, " (" + z.disabled_count + " off)") : null] : "", class: "right", tdClass: "right" },
@@ -38,8 +39,10 @@ export async function render(el, params, query) {
     h("div", { class: "page-head" },
       h("div", { class: "grow" }, h("h1", null, "Zones"), h("div", { class: "muted" }, zones.length + " zones")),
       h("div", { class: "actions" }, filter, views.length ? viewSel : null, typeSel,
-        can("zones", true) ? h("button", { class: "primary", onclick: () => newZoneDialog(views, zones, settings) }, "New zone") : null)),
-    h("div", { class: "panel" }, list));
+        can("zones", true) ? [h("button", { title: "A zone for the PTR records of a network: Jarl lists the networks your records use", onclick: () => newZoneDialog(views, zones, settings, { kind: "reverse" }) }, "New reverse zone"), " ",
+          h("button", { class: "primary", onclick: () => newZoneDialog(views, zones, settings) }, "New zone")] : null)),
+    h("div", { class: "panel" }, list),
+    suggestions.length && can("zones", true) ? suggestPanel(suggestions, views) : null);
   draw();
   if (query.get("new")) {
     // Drop ?new=1 so re-rendering after the zone is created doesn't open
@@ -49,16 +52,38 @@ export async function render(el, params, query) {
   }
 }
 
-// preset.view picks the view (opened from a view's page).
+// preset.view picks the view (opened from a view's page), preset.kind
+// "reverse" starts with a reverse zone.
 export async function newZoneDialog(views, zones, settings, preset = {}) {
   const err = h("div");
   // The zone's name matters most and is easy to get wrong, so the dialog
   // asks for a domain or a network and shows the resulting zone name.
-  let kind = "forward";
+  let kind = preset.kind === "reverse" ? "reverse" : "forward";
   const name = input({ placeholder: "adbraun.lol", class: "mono", autocomplete: "off", spellcheck: "false" });
   const nameLabel = h("label", { for: "zone-name" }, "Domain");
   name.id = "zone-name";
   const preview = h("div", { class: "name-preview", "aria-live": "polite" });
+  // For a reverse zone: sizes to pick from, and the networks the records
+  // use without a reverse zone, in every view (docs/reverse.md).
+  const helper = h("div", { class: "reverse-helper" });
+  // The networks per view picked ("" for all views): a chosen view's list
+  // also has the addresses only other views' records use.
+  const candsBy = {};
+  let cands = null;
+  const candQ = input({ type: "search", placeholder: "Search: an address, a name or a view", class: "small", style: { marginBottom: "6px" } });
+  candQ.addEventListener("input", () => drawHelper());
+  const loadCands = () => {
+    const k = view.value || "";
+    if (candsBy[k]) { cands = candsBy[k]; return drawHelper(); }
+    get("/reverse-zones/suggestions", draftQuery({ all: 1, view: k || undefined })).catch(() => []).then((c) => {
+      candsBy[k] = c;
+      if ((view.value || "") === k) { cands = c; drawHelper(); }
+    });
+  };
+  // sizeFrom is the address the size buttons work from: a record's, once a
+  // network was picked, so a /48 made smaller becomes that record's /64,
+  // not the /48's first one.
+  let sizeFrom = null;
   const kindButtons = h("div", { class: "segmented", role: "group", "aria-label": "Kind of zone" });
   const type = select([["primary", "primary (Jarl manages the records)"], ["secondary", "secondary (copy from another server)"], ["forward", "forward (send queries to other resolvers)"], ["stub", "stub"], ["static-stub", "static-stub"], ["mirror", "mirror"], ["hint", "hint (root hints)"], ["in-view", "in-view (share a zone from an earlier view)"]], "primary");
   const view = select([["", views.length ? "– choose a view –" : "(no views)"], ...views.map((v) => [v.name, v.name])], preset.view || (views.length === 1 ? views[0].name : ""));
@@ -77,6 +102,8 @@ export async function newZoneDialog(views, zones, settings, preset = {}) {
   const syncLink = () => { linkBox.style.display = cloneSel.value ? "" : "none"; };
   cloneSel.addEventListener("change", syncLink);
   const comment = input();
+  const fill = checkbox("Add a PTR record for each address the view's A and AAAA records use in this network", true);
+  const fillRow = field("PTR records", fill, "Names already in your zones, so the reverse zone answers from the start. Leave it off to add them yourself.");
   const updateClones = () => {
     // Records can only be copied into a single zone.
     const n = (kind === "reverse" ? reverseZoneFor(name.value).name || "-" : name.value.trim().toLowerCase().replace(/\.$/, "")) + ".";
@@ -144,20 +171,61 @@ export async function newZoneDialog(views, zones, settings, preset = {}) {
     nameLabel.textContent = k === "reverse" ? "Network" : "Domain";
     name.placeholder = k === "reverse" ? "10.10.0.0/24  or  2001:db8:1::/48" : "adbraun.lol";
     for (const b of kindButtons.children) b.classList.toggle("active", b.dataset.kind === k);
+    syncFill();
+    if (k === "reverse") loadCands();
+    drawHelper();
+    if (views.length) view.options[0].textContent = k === "reverse" ? "– the private view that uses these addresses –" : "– choose a view –";
     check();
     name.focus();
   };
   for (const [k, label, title] of [["forward", "Domain", "Names to addresses, e.g. adbraun.lol"], ["reverse", "Reverse zone", "Addresses to names (PTR records) for a network"]]) {
     kindButtons.append(h("button", { type: "button", dataset: { kind: k }, title, class: k === kind ? "active" : "", onclick: () => setKind(k) }, label));
   }
-  name.addEventListener("input", () => { mount(err); updateClones(); check(); });
-  view.addEventListener("change", check);
+  const changed = () => { mount(err); updateClones(); check(); drawHelper(); };
+  const typed = () => { sizeFrom = null; changed(); };
+  const drawHelper = () => {
+    if (kind !== "reverse") return mount(helper);
+    const v = name.value.trim();
+    const isNet = v && maskNetwork(v, 32) !== null;
+    const v6 = v.includes(":");
+    const bits = Number(v.split("/")[1]);
+    const sizes = isNet ? h("div", { class: "size-chips" }, h("span", { class: "muted small" }, "Size: "),
+      (v6 ? [[48, "a whole site (all its /64s)"], [56, "a smaller delegation"], [64, "one subnet"], [128, "one address"]] : [[16, "a /16"], [24, "one network"], [32, "one address"]])
+        .map(([b, title]) => h("button", { type: "button", class: "small" + (bits === b ? " active" : ""), title, onclick: () => { name.value = maskNetwork(sizeFrom || name.value, b); changed(); } }, "/" + b)),
+      sizeFrom ? h("span", { class: "muted small" }, " around " + sizeFrom) : null) : null;
+    const q = candQ.value.trim().toLowerCase();
+    // Yours first, then the networks with the most records.
+    const list = (cands || []).filter((c) => !q || [c.prefix, c.zone, c.view, c.hidden, ...c.samples].join(" ").toLowerCase().includes(q))
+      .sort((a, b) => (a.group === "yours" ? 0 : 1) - (b.group === "yours" ? 0 : 1) || b.fill - a.fill);
+    const shown = list.slice(0, 15);
+    mount(helper, sizes,
+      (cands || []).length > 8 ? candQ : null,
+      shown.length ? h("div", { class: "cands" },
+        h("div", { class: "muted small" }, "Networks your records use without a reverse zone" + (view.value ? " in view " + view.value : "") + ": pick one, then change its size if you need"),
+        shown.map((c) => h("button", { type: "button", class: "cand", title: c.why, onclick: () => {
+          name.value = c.prefix;
+          sizeFrom = c.samples.length ? c.samples[0].split(" ")[0] : null;
+          if (views.length && c.view) view.value = c.view;
+          changed();
+        } },
+          h("span", { class: "mono" }, c.prefix),
+          views.length && !view.value ? h("span", { class: "muted" }, "  " + c.view) : null,
+          h("span", { class: "muted small" }, "  " + c.fill + " PTR" + (c.samples.length ? " · " + c.samples.slice(0, 2).join(", ") : "")),
+          c.hidden ? [" ", badge(c.hidden, "off")] : null)),
+        list.length > shown.length ? h("div", { class: "muted small" }, "… and " + (list.length - shown.length) + " more: search to find one") : null)
+        : q && cands && cands.length ? h("div", { class: "muted small" }, "No network matches " + JSON.stringify(candQ.value.trim()) + ".")
+        : cands && !list.length ? h("div", { class: "muted small" }, "Every address your records use" + (view.value ? " in view " + view.value : "") + " has a reverse zone.") : null);
+  };
+  name.addEventListener("input", typed);
+  view.addEventListener("change", () => { check(); if (kind === "reverse") loadCands(); else drawHelper(); });
+  const glueRow = field("Name server addresses", nsAddr, "Optional, for name servers inside this zone: 'ns1 192.0.2.1' per line (glue).");
+  const cloneRow = field("Copy records from", cloneWrap, "For split-horizon setups: start with the records of this zone in another view. Linked, Jarl keeps the shared records the same in both (docs/views.md#linked-zones).");
   const rows = {
     primary: [field("Name servers", ns, "One per line. Become the zone's NS records; the first is the SOA primary name server."),
-      field("Name server addresses", nsAddr, "Optional, for name servers inside this zone: 'ns1 192.0.2.1' per line (glue)."),
+      glueRow,
       field("SOA contact", contact, "Email address of the zone's administrator."),
       field("Default TTL", ttl, "Seconds, used by records without their own TTL."),
-      field("Copy records from", cloneWrap, "For split-horizon setups: start with the records of this zone in another view. Linked, Jarl keeps the shared records the same in both (docs/views.md#linked-zones).")],
+      cloneRow],
     secondary: [field("Primary servers", primaries, "One per line: address [port N] [key NAME].")],
     stub: [field("Primary servers", primaries, "One per line.")],
     mirror: [field("Primary servers", primaries, "One per line (not needed for the root zone).")],
@@ -167,7 +235,13 @@ export async function newZoneDialog(views, zones, settings, preset = {}) {
     "in-view": [field("Share from view", inView, "The zone must exist in an earlier view.")],
   };
   const typeRows = h("div", { class: "form-grid" });
+  const syncFill = () => {
+    for (const n of fillRow) if (n) n.style.display = kind === "reverse" && type.value === "primary" ? "" : "none";
+    // Glue and copying a zone from another view are for domains.
+    for (const n of [...glueRow, ...cloneRow]) if (n) n.style.display = kind === "reverse" ? "none" : "";
+  };
   const drawType = () => {
+    syncFill();
     mount(typeRows, rows[type.value] || []);
     if (type.value === "hint" && !name.value.trim()) name.value = ".";
     check();
@@ -177,13 +251,15 @@ export async function newZoneDialog(views, zones, settings, preset = {}) {
   const body = h("div", null,
     h("div", { class: "form-grid" },
       h("label", null, "Kind"), h("div", null, kindButtons),
-      nameLabel, h("div", null, name, preview),
+      nameLabel, h("div", { class: "grid-cell" }, name, preview, helper),
       views.length ? field("View", view) : null,
       field("Type", type),
+      fillRow,
       field("Comment", comment)),
     h("div", { style: { marginTop: "8px" } }, typeRows),
     err);
-  await modal("New zone", body, [
+  if (kind === "reverse") setKind("reverse");
+  await modal(kind === "reverse" ? "New reverse zone" : "New zone", body, [
     { label: "Cancel", value: null },
     { label: "Create zone", kind: "primary", onclick: async () => {
       const t = type.value;
@@ -197,6 +273,7 @@ export async function newZoneDialog(views, zones, settings, preset = {}) {
       if (view.value) data.view = view.value;
       const opts = [];
       const list = (ta) => lines(ta.value).map((l) => l.replace(/;$/, "") + ";").join(" ");
+      if (t === "primary" && kind === "reverse" && fill.input.checked) data.fill = true;
       if (t === "primary") {
         data.nameservers = lines(ns.value);
         if (contact.value.trim()) data.soa = { rname: contact.value.trim() };
@@ -229,6 +306,7 @@ export async function newZoneDialog(views, zones, settings, preset = {}) {
           ? await changeMany(zoneName.map((n) => ({ op: "zone.create", data: { ...data, name: n } })), "reverse zones for " + name.value.trim())
           : await change("POST", "/zones", data);
         toast(describeResult(r));
+        (r.warnings || []).forEach((w) => toast(w, "warn", 10000));
         rerender();
         return true;
       } catch (e) {
@@ -268,3 +346,84 @@ export function dnssecLock(z) {
 export function pendingBadge(kind) {
   return badge({ add: "pending: new", change: "pending: changed", delete: "pending: delete", disable: "pending: disable", enable: "pending: enable" }[kind] || kind, kind === "delete" ? "err" : "warn");
 }
+
+// suggestPanel lists the reverse zones the private views lack for their
+// records' addresses, to create filled with PTR records (docs/reverse.md):
+// networks that are yours, and public addresses, which may be a web
+// host's, to create one by one or dismiss.
+function suggestPanel(sugg, views) {
+  const create = async (list) => {
+    const reqs = list.map((s) => ({ op: "zone.create", data: { name: s.prefix, view_id: s.view_id || undefined, fill: true } }));
+    try {
+      const r = reqs.length === 1 ? await change("POST", "/zones", reqs[0].data) : await changeMany(reqs, plural(reqs.length, "reverse zone"));
+      toast(describeResult(r));
+      (r.warnings || []).forEach((w) => toast(w, "warn", 10000));
+      rerender();
+    } catch (e) { toast(e.message, "err", 8000); }
+  };
+  const dismiss = async (s) => {
+    try {
+      const r = await change("POST", "/reverse-zones/dismiss", { view_id: s.view_id || undefined, prefix: s.prefix });
+      toast(describeResult(r));
+      rerender();
+    } catch (e) { toast(e.message, "err", 8000); }
+  };
+  const cols = (pub) => [
+    views.length ? { label: "View", render: (s) => s.view } : null,
+    { label: pub ? "Address" : "Network", render: (s) => [h("span", { class: "mono" }, pub ? s.prefix.replace(/\/(32|128)$/, "") : s.prefix), pub ? null : h("div", { class: "muted small" }, s.why)] },
+    { label: "Zone", render: (s) => h("span", { class: "mono small" }, s.zone) },
+    { label: pub ? "Name" : "PTR records", render: (s) => pub ? h("span", { class: "mono small" }, s.samples.map((x) => x.split(" ")[1]).join(", ")) : [String(s.fill), s.samples.length ? h("div", { class: "muted small mono" }, s.samples.join(", ") + (s.fill > s.samples.length ? ", …" : "")) : null] },
+    { label: "", render: (s) => [h("button", { class: "small", onclick: () => create([s]) }, "Create"), pub ? [" ", h("button", { class: "small", title: "Not yours (a web host's, say): don't suggest it again", onclick: () => dismiss(s) }, "Dismiss")] : null], tdClass: "actions-cell" },
+  ].filter(Boolean);
+  const yours = sugg.filter((s) => s.group === "yours");
+  const pub = sugg.filter((s) => s.group !== "yours");
+  return h("div", { class: "panel" },
+    h("div", { class: "page-head" }, h("h2", { class: "grow" }, "Missing reverse zones"),
+      yours.length > 1 ? h("div", { class: "actions" }, h("button", { onclick: () => create(yours) }, "Create all " + yours.length)) : null),
+    h("p", { class: "muted small" }, "Your records use these addresses, but no reverse zone answers \"which host has this address?\" for them" + (views.length ? " in their view" : "") + ". Jarl creates each with a PTR record for every address there. Only your own clients ask this server: the internet asks whoever owns the addresses."),
+    yours.length ? table(cols(false), yours) : null,
+    pub.length ? publicGroup(pub, cols(true), create) : null);
+}
+
+// publicGroup lists the public addresses, collapsed: there can be hundreds
+// (a web host's), so it has a search, shows 25 at a time, and dismisses
+// what the search found at once.
+function publicGroup(pub, cols, create) {
+  const PAGE = 25;
+  let limit = PAGE;
+  const q = input({ type: "search", placeholder: "Search: an address, a name or a view", class: "small", style: { width: "300px" } });
+  const body = h("div");
+  const match = () => {
+    const t = q.value.trim().toLowerCase();
+    return pub.filter((s) => !t || [s.prefix, s.zone, s.view, ...s.samples].join(" ").toLowerCase().includes(t));
+  };
+  const dismissAll = async (list) => {
+    const byView = new Map();
+    for (const s of list) {
+      const k = s.view_id || 0;
+      if (!byView.has(k)) byView.set(k, []);
+      byView.get(k).push(s.prefix);
+    }
+    if (!await confirmDialog("Dismiss " + plural(list.length, "address", "addresses"), "Jarl stops suggesting reverse zones for " + (list.length === 1 ? list[0].prefix : list.length + " public addresses" + (q.value.trim() ? " matching " + JSON.stringify(q.value.trim()) : "")) + ". Bring one back with: jarl zone suggest-reverse --undismiss NETWORK --view VIEW.", "Dismiss")) return;
+    try {
+      const ops = [...byView].map(([vid, prefixes]) => ({ op: "reverse.dismiss", data: { view_id: vid || undefined, prefixes } }));
+      toast(describeResult(await changeMany(ops, "dismiss " + plural(list.length, "reverse zone suggestion"))));
+      rerender();
+    } catch (e) { toast(e.message, "err", 8000); }
+  };
+  const draw = () => {
+    const list = match();
+    const shown = list.slice(0, limit);
+    mount(body,
+      h("div", { class: "compare-controls" }, q,
+        list.length ? h("button", { class: "small", title: "Not yours: stop suggesting all of these", onclick: () => dismissAll(list) }, list.length === pub.length ? "Dismiss all " + list.length : "Dismiss these " + list.length) : null),
+      shown.length ? table(cols, shown) : h("div", { class: "muted small" }, "No address matches."),
+      list.length > shown.length ? h("button", { class: "small", onclick: () => { limit += PAGE; draw(); } }, "Show " + Math.min(PAGE, list.length - shown.length) + " more (of " + (list.length - shown.length) + ")") : null);
+  };
+  q.addEventListener("input", () => { limit = PAGE; draw(); });
+  draw();
+  return h("details", { class: "compare-only", open: pub.length <= 10 },
+    h("summary", null, h("strong", null, "Public addresses: " + pub.length), h("span", { class: "muted small" }, " · create a zone only for an address that is yours; dismiss the others (a web host's)")),
+    h("p", { class: "muted small" }, "Jarl can't tell your own servers from someone else's. Each gets a zone of its own: the rest of its network belongs to others."),
+    body);
+}

internal/web/static/assets/style.css

@@ -564,6 +564,29 @@ ul.probes > li { padding: 6px 0; border-bottom: 1px solid var(--border); }
 ul.probes > li .msg { margin: 6px 0 0; }
 
 /* Comparing a zone across views. */
-table.compare td.compare-cell { vertical-align: top; }
+table.compare td { vertical-align: top; }
+/* The same name and type columns in every section, so they line up. */
+table.compare { table-layout: auto; width: 100%; }
+table.compare tr > :nth-child(1) { width: 18ch; }
+table.compare tr > :nth-child(2) { width: 8ch; }
 table.compare td.compare-cell button { margin-top: 4px; }
+/* One line per record: a long TXT record is cut, with the whole of it on hover. */
+table.compare .oneline { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 46ch; }
+.compare-actions { margin-top: 4px; }
+.compare-controls { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; margin-bottom: 12px; }
+.compare-controls label { color: var(--muted); }
+ul.compare-summary { margin: 0 0 12px; padding-left: 18px; }
+details.compare-only { margin: 12px 0; }
+details.compare-only summary { cursor: pointer; padding: 4px 0; }
 table.compare tr.muted td { color: var(--muted); }
+
+/* Text that wraps anywhere, e.g. long statements in the Added by Jarl table. */
+pre.wrap { white-space: pre-wrap; word-break: break-all; }
+
+/* New reverse zone: sizes and the networks the records use. */
+.reverse-helper { margin-top: 6px; }
+.form-grid > .grid-cell { min-width: 0; }
+.size-chips { display: flex; gap: 4px; align-items: center; flex-wrap: wrap; margin-bottom: 6px; }
+.size-chips button.active { background: var(--accent); border-color: var(--accent); color: var(--accent-text); }
+.cands { display: flex; flex-direction: column; gap: 3px; max-height: 260px; overflow-y: auto; }
+.cands button.cand { flex-shrink: 0; text-align: left; font-weight: normal; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

scripts/e2e.sh

@@ -418,11 +418,28 @@ expect_dig "now every view's" "10.1.1.1" -k $E/external.key linked.adbraun.test
 run "--view all changes a link once" 0 $J record set adbraun.test linked A 10.1.1.2 --view all
 contains "linked with internal"
 expect_dig "both views" "10.1.1.2" -k $E/external.key linked.adbraun.test A
-run "zone diff: what differs between the views" 0 $J zone diff adbraun.test
-contains "ns1  *A  *127.0.0.1 \\[local, id [0-9]*\\]  *203.0.113.1 \\[local, id [0-9]*\\]"
-contains "names and types differ, [0-9]* are the same; linked"
-run "the compare API" 0 curl -sf -H "Authorization: Bearer $(cat $E/admin.token)" "http://127.0.0.1:$HTTP/api/v1/zones/adbraun.test/compare?view=internal&all=1"
+run "zone diff: internal compared with external" 0 $J zone diff adbraun.test
+contains "^adbraun.test in internal, compared with external$"
+contains "^  linked: a difference is a view's own records"
+contains "^  external: [1-9][0-9]* answered differently, [0-9]* only in internal, [0-9]* only in external, [0-9]* the same"
+contains "^ANSWERED DIFFERENTLY"
+contains "^  ns1 A$"
+contains "^    internal  127.0.0.1  \\[local, id [0-9]*\\]"
+contains "^    external  203.0.113.1  \\[local, id [0-9]*\\]"
+contains "the same (--all lists them)"
+run "zone diff from external" 0 $J zone diff adbraun.test --view external
+contains "^adbraun.test in external, compared with internal"
+run "zone diff for one name" 0 $J zone diff adbraun.test ns1 A
+contains "^  ns1 A$"
+not_contains "the same (--all"
+run "a long TXT record" 0 $J record add adbraun.test longtxt TXT "$(printf 'x%.0s' $(seq 300))" --view internal --local
+run "zone diff --wide shows it whole" 0 $J zone diff adbraun.test longtxt --wide
+contains "x\\{250\\}"
+run "the compare API" 0 curl -sf -H "Authorization: Bearer $(cat $E/admin.token)" "http://127.0.0.1:$HTTP/api/v1/zones/adbraun.test/compare?view=internal&with=external&all=1"
 contains '"linked":true'
+contains '"base":"internal"'
+contains '"same_rows":\['
+run "remove the long TXT" 0 $J record delete adbraun.test longtxt TXT --view internal -y
 run "a shared delete" 0 $J record delete adbraun.test linked A --view external -y
 expect_dig "gone from internal too" "" linked.adbraun.test A
 run "zone unlink" 0 $J zone unlink adbraun.test --view external
@@ -453,6 +470,13 @@ contains "rate-limit { responses-per-second 10; log-only yes; };"
 run "exposure: log-only now" 0 $J exposure
 contains "^external  *public  *log-only"
 contains "exposure_rate_limit_log_only"
+# Statistics are off here; render/stats_test.go covers their statements.
+run "what Jarl adds by itself" 0 $J option generated
+contains "^include .*keys.conf"
+contains 'match-clients { !key "jarl-view-external"; key "jarl-view-internal"; ... };'
+not_contains "statistics-channels"
+run "generated, as JSON" 0 $J option generated -o json
+contains '"setting": "always, when there are views"'
 run "fix: start enforcing" 0 $J exposure fix external exposure_rate_limit_log_only
 contains "responses-per-second 10; }"
 # A burst of identical queries in the external view (signed with its key):
@@ -633,6 +657,75 @@ expect_dig "enabled zone served again" "192.0.2.70" www.parked.test A
 expect_dig "with the change made while disabled" "192.0.2.71" api.parked.test A
 run "delete it" 0 $J zone delete parked.test --view internal --yes
 
+# Reverse zones made easy (docs/reverse.md): suggested from the records'
+# addresses, created in the right view and filled, PTRs kept in step.
+run "zone for reverse" 0 $J zone create revtest.test --view internal --ns ns1.adbraun.test.
+run "its hosts" 0 $J record add revtest.test nas A 10.99.1.10 --view internal
+run "a second name for nas" 0 $J record add revtest.test files A 10.99.1.10 --view internal
+run "another host" 0 $J record add revtest.test pi A 10.99.1.11 --view internal
+run "and IPv6" 0 $J record add revtest.test nas AAAA fdab:99:0:10::10 --view internal
+run "suggest-reverse" 0 $J zone suggest-reverse
+contains "^yours  *internal  *10.99.1.0/24  *1.99.10.in-addr.arpa  *2  *10.99.1.10 files.revtest.test, 10.99.1.11 pi.revtest.test"
+contains "^yours  *internal  *fdab:99::/48  *0.0.0.0.9.9.0.0.b.a.d.f.ip6.arpa  *1"
+run "create it without a view, filled" 0 $J zone create 10.99.1.0/24 --fill
+contains "10.99.1.10 has several names"
+run "it went to the internal view" 0 $J zone show 1.99.10.in-addr.arpa
+contains "^View:  *internal"
+contains "^Network:  *10.99.1.0/24"
+not_contains "Missing PTRs"
+expect_dig "filled: PTR for pi" "pi.revtest.test." -x 10.99.1.11
+expect_dig "filled: one name for nas" "files.revtest.test." -x 10.99.1.10
+run "an empty /48 zone" 0 $J zone create fdab:99::/48
+run "shows what it lacks" 0 $J zone show fdab:99::/48
+contains "^Missing PTRs:  *1 "
+run "fill-ptr" 0 $J zone fill-ptr fdab:99::/48
+expect_dig "filled later: IPv6 PTR" "nas.revtest.test." -x fdab:99:0:10::10
+run "fill-ptr again: nothing to add (exit 6)" 6 $J zone fill-ptr fdab:99::/48
+contains "nothing to add"
+run "keep PTRs in step" 0 $J zone update revtest.test --view internal --auto-ptr
+run "zone show says so" 0 $J zone show revtest.test --view internal
+contains "^PTR records:  *kept in step"
+run "a new host" 0 $J record add revtest.test cam A 10.99.1.12 --view internal
+expect_dig "its PTR came along" "cam.revtest.test." -x 10.99.1.12
+CAM=$($J record list revtest.test --view internal -o json | python3 -c 'import json,sys; print([r["id"] for r in json.load(sys.stdin) if r["name"].startswith("cam.")][0])')
+run "the host moves" 0 $J record update $CAM --data 10.99.1.13
+expect_dig "PTR followed: new address" "cam.revtest.test." -x 10.99.1.13
+expect_dig "PTR followed: old address gone" "" -x 10.99.1.12
+run "the host goes" 0 $J record delete --id $CAM
+expect_dig "PTR gone with it" "" -x 10.99.1.13
+run "a web host's address" 0 $J record add revtest.test blog A 185.199.108.153 --view internal
+run "suggested as public" 0 $J zone suggest-reverse
+contains "^public  *internal  *185.199.108.153/32"
+run "two more web host addresses" 0 $J record add revtest.test docs A 185.199.109.153 --view internal
+run "and" 0 $J record add revtest.test pages A 185.199.110.153 --view internal
+run "dismiss three at once" 0 $J zone suggest-reverse --dismiss 185.199.108.153/32,185.199.109.153/32 --dismiss 185.199.110.153/32 --view internal
+run "gone from the suggestions" 0 $J zone suggest-reverse
+not_contains "185.199."
+run "suggest-reverse --create: yours only" 0 $J zone suggest-reverse --create
+run "none of yours missing now" 0 $J zone suggest-reverse
+not_contains "^yours"
+run "a view can turn suggestions off" 0 $J view update internal --reverse-suggestions=false
+run "then none for it" 0 $J zone suggest-reverse
+not_contains "internal"
+run "but --all still lists its networks" 0 $J zone suggest-reverse --all --view internal
+contains "^public  *internal  *185.199.108.153/32 .* suggestions off"
+run "and back on" 0 $J view update internal --reverse-suggestions
+# An address only the external view has a record for: a reverse zone in
+# the internal view can still name it.
+run "an AAAA only in external" 0 $J record add adbraun.test vps AAAA 2600:3c01::f03c:93ff:fe2b:1 --view external
+run "offered for internal" 0 $J zone suggest-reverse --all --view internal
+contains "2600:3c01::f03c:93ff:fe2b:1/128 .*records in external"
+run "created in internal, filled from external's record" 0 $J zone create 2600:3c01::f03c:93ff:fe2b:1/128 --view internal --fill
+expect_dig "internal answers its PTR" "vps.adbraun.test." -x 2600:3c01::f03c:93ff:fe2b:1
+# A zone created inside another takes the parent's records under it.
+run "a /16 reverse zone" 0 $J zone create 10.88.0.0/16 --view internal
+run "with a PTR made by hand" 0 $J record add 10.88.0.0/16 10.88.5.5 PTR printer.revtest.test --view internal
+expect_dig "the /16 answers" "printer.revtest.test." -x 10.88.5.5
+run "a /24 inside it" 0 $J zone create 10.88.5.0/24 --view internal
+run "the PTR moved" 0 $J record list 10.88.5.0/24 --view internal
+contains "printer.revtest.test."
+expect_dig "and still answers, from the /24" "printer.revtest.test." -x 10.88.5.5
+
 # Blocking (docs/blocking.md). It only changes answers to recursive
 # queries, so these ask with recursion and look at which policy zone (if
 # any) the answer came from.