Found by running the drill on a real host, which I could not do before.
The unit is Type=oneshot with no RemainAfterExit, so systemd marks it
'inactive (dead)' the moment ExecStart succeeds. The rules are applied and the
box-to-box drop is live, and the unit still reads as though it died. That is
precisely the question people ask this unit: drill.sh's own failure hint sends
you to 'systemctl status box-firewall.service' to find out whether the firewall
came up, and today the honest answer and the alarming one look identical.
setup-host.sh already believed this was set — 'The unit is RemainAfterExit, so
once it has run it stays "active" forever' — and reasoned from it to explain why
it uses restart instead of 'enable --now'. The reasoning is right and the
restart is right; only the unit was missing the line the comment assumed.
Verified live: before, 'nft list table bridge box' showed the drop present while
is-active said inactive. After, is-active says active (exited) with the drop
still present, and restart still re-applies.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>