abrown38andClaude Opus 5.5
34292eeebb
Zones, address sets (IPv4 and IPv6 mixed, dynamic sets with timeouts) and services, ordered rules in the early, input, forward and output chains, port forwards with hairpin NAT and IPv6 pinholes, source NAT, redirects, and switchable built-ins (loopback, conntrack, ICMPv6, antispoofing, MSS clamping, DHCPv6 client, flowtable). Every change is validated, checked with nft -c and applied in one transaction to Housecarl's own table, inet housecarl; changes made over the network roll back unless confirmed, and the confirmed ruleset is loaded at boot by housecarl-ruleset.service. An empty configuration applies nothing. Also: hit counters and the drop log (nflog), 'hc import' of an existing nftables ruleset and 'hc takeover', the hc CLI, the REST API and the web UI, users, scoped tokens (sets:write:NAME), the audit log, the web UI's certificate through Jarl, Debian packages, docs, unit tests with real nft 1.1.3, and an e2e test with real traffic (71 checks). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
140 lines
4.7 KiB
Markdown
140 lines
4.7 KiB
Markdown
# Running Housecarl
|
|
|
|
## The services
|
|
|
|
```sh
|
|
systemctl status housecarl # housecarld: the API, the web UI, the log
|
|
journalctl -u housecarl -f
|
|
systemctl reload housecarl # reread the TLS certificate
|
|
systemctl status housecarl-ruleset # the ruleset loaded at boot
|
|
```
|
|
|
|
The firewall itself is the kernel's: it stays in force while housecarld
|
|
is stopped, restarted or upgraded. Without housecarld there is no API,
|
|
no web UI, no log and no probation timer.
|
|
|
|
housecarld logs each change it applies, rollbacks, and what it couldn't
|
|
apply. When it starts, it applies the configuration again (rolling back
|
|
first what was on probation when it stopped).
|
|
|
|
## Changes on probation
|
|
|
|
Changes made over the network roll back unless confirmed
|
|
([design.md](design.md#not-locking-yourself-out)):
|
|
|
|
```sh
|
|
hc status # Probation: 2 changes roll back in 97s unless confirmed
|
|
hc confirm
|
|
hc rollback # or undo them now
|
|
```
|
|
|
|
The web UI shows a banner with a countdown and both buttons. A rollback
|
|
is in the history, as an undo by `housecarl` via `rollback`, so it can be
|
|
undone like any change.
|
|
|
|
If you are cut off by a change: wait. When the time is up, the previous
|
|
ruleset comes back by itself. If you are cut off by a confirmed change,
|
|
use the console, or SSH from a source the rules still let in:
|
|
|
|
```sh
|
|
sudo hc history list
|
|
sudo hc history undo 42
|
|
```
|
|
|
|
## The ruleset at boot
|
|
|
|
A confirmed ruleset (or one changed through the socket) is saved to
|
|
`/var/lib/housecarl/ruleset.nft`, which `housecarl-ruleset.service`
|
|
loads before the network comes up. To see what would load:
|
|
|
|
```sh
|
|
sudo cat /var/lib/housecarl/ruleset.nft
|
|
sudo nft -c -f /var/lib/housecarl/ruleset.nft # check it
|
|
```
|
|
|
|
Dynamic sets start empty after a reboot.
|
|
|
|
Keep Debian's `nftables.service` disabled, or `/etc/nftables.conf`
|
|
without `flush ruleset`: otherwise it deletes Housecarl's table at
|
|
boot. `housecarl-ruleset.service` runs after it, which covers the
|
|
ordinary case.
|
|
|
|
## Hits
|
|
|
|
Every rule, NAT rule, built-in and policy has a counter. `hc rule list`,
|
|
`hc forward list` and the web UI show packets; `hc counters` shows them
|
|
all, with bytes. They count from housecarld's start, and carry across
|
|
changes to the ruleset.
|
|
|
|
## The log
|
|
|
|
Rules with `--log` (Log in the web UI) and, with `hc settings set
|
|
--log-drops on`, what the input and forward policies drop (at most 10
|
|
packets a second) are logged:
|
|
|
|
```sh
|
|
hc log -f
|
|
hc log --search 198.51.100.7
|
|
```
|
|
|
|
```
|
|
10:02:13 hc input #95 drop: wan - 198.51.100.7:53868 -> 203.0.113.7:22 tcp syn
|
|
10:02:15 hc forward policy drop: wan enp2s0 198.51.100.9:443 -> 10.0.10.20:51432 tcp
|
|
```
|
|
|
|
The packets go to netlink log group 4171, where housecarld reads them;
|
|
the last 2000 are kept in memory. They aren't written to the kernel log
|
|
or the journal. A rule's log isn't rate-limited: on a busy rule, give it
|
|
a limit, or log only new connections (`--state new`).
|
|
|
|
## When something doesn't get through
|
|
|
|
1. `hc log -f` with `--log-drops on`: is it dropped by a policy (no rule
|
|
accepted it), or by a rule (its number is in the line)?
|
|
2. `hc rule list forward` (or `input`): hits on the rule you expect?
|
|
3. `hc ruleset`: the rule as nftables sees it, with the zones' interfaces
|
|
and the sets' families.
|
|
4. `hc status`: other tables. A Docker or Incus table, or an old one,
|
|
can drop what Housecarl accepts.
|
|
5. Port forwards: `hc forward list` hits, and the inside host's own
|
|
firewall and default route (answers must go back through Housecarl).
|
|
|
|
## Backups
|
|
|
|
`housecarl-backup.timer` runs `housecarld backup` daily. It writes a
|
|
consistent copy of the database to `backup.dir`
|
|
(`/var/backups/housecarl/housecarl-<time>.db`), and deletes those older
|
|
than `backup.retention` (30 days), keeping at least
|
|
`backup.keep_at_least` (7). A backup holds everything: configuration,
|
|
history, users, tokens (hashed) and the audit log.
|
|
|
|
```sh
|
|
sudo -u housecarl housecarld backup # now
|
|
sudo -u housecarl housecarld backup /tmp/h.db # to a file of your choice
|
|
sudo systemctl disable --now housecarl-backup.timer # no daily backups
|
|
```
|
|
|
|
To **restore**, stop housecarld first; restore refuses to replace the
|
|
database under it:
|
|
|
|
```sh
|
|
sudo systemctl stop housecarl
|
|
sudo -u housecarl housecarld restore /var/backups/housecarl/housecarl-20261014T020000Z.db
|
|
sudo systemctl start housecarl
|
|
```
|
|
|
|
housecarld applies the restored configuration when it starts. The old
|
|
database is kept next to it as `housecarl.db.before-restore-<time>`.
|
|
|
|
## Upgrades
|
|
|
|
`apt upgrade` restarts a running housecarld. A new version upgrades the
|
|
database when it starts, and an older one refuses a database a newer one
|
|
has upgraded: restore a backup to go back.
|
|
|
|
## Checks
|
|
|
|
`housecarld check` validates the configuration in the database against
|
|
this machine's interfaces, the same checks as `hc status` shows
|
|
([validation.md](validation.md)).
|