deploy/systemd/docker.service.d/mealquest-firewall.conf

@@ -1,3 +0,0 @@
-# Re-apply the MealQuest DOCKER-USER rules after every docker (re)start.
-[Service]
-ExecStartPost=/usr/local/sbin/mealquest-firewall

deploy/systemd/mealquest-firewall.service

@@ -1,7 +1,17 @@
+# Applies the MealQuest DOCKER-USER rules (/usr/local/sbin/mealquest-firewall).
+#
+# PartOf= re-runs this unit whenever docker.service is stopped or restarted,
+# and WantedBy=docker.service starts it whenever docker.service starts. Both
+# are one-way: a failure here fails this unit visibly and never fails
+# docker.service.
+#
+# Start MealQuest only after this unit has succeeded:
+#   systemctl start mealquest-firewall && docker compose up -d
 [Unit]
 Description=Restrict MealQuest port 8090 to Traefik (DOCKER-USER)
 After=docker.service
 Requires=docker.service
+PartOf=docker.service
 
 [Service]
 Type=oneshot
@@ -9,4 +19,4 @@ RemainAfterExit=yes
 ExecStart=/usr/local/sbin/mealquest-firewall
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=multi-user.target docker.service

deploy/systemd/mealquest-firewall.sh

@@ -1,21 +1,29 @@
 #!/bin/sh
-# Restrict the MealQuest published host port to Traefik (10.60.1.33) and the
-# Docker host itself (10.60.1.14); drop every other source.
+# Restrict the MealQuest published host port (10.60.1.14:8090) to Traefik
+# (10.60.1.33) and the Docker host itself (10.60.1.14); drop every other
+# source.
 #
-# DOCKER-USER runs after Docker's DNAT, so the destination port there is the
-# container port (8080), not the published one. Match the original
-# destination port with conntrack instead of --dport.
+# DOCKER-USER runs after Docker's DNAT, so the destination there is the
+# container address and port, not the published ones. Match the original
+# destination address and port with conntrack instead of -d/--dport.
 #
-# Idempotent: each rule is checked (-C) before it is added, so re-runs add
-# nothing. Installed as /usr/local/sbin/mealquest-firewall.
+# The rules must sit at the top of DOCKER-USER, ahead of any other project's
+# rules (an earlier RETURN or DROP would decide MealQuest traffic first).
+# Every run deletes all rules tagged with the mealquest-firewall comment and
+# re-inserts them at positions 1-3, so re-runs leave the same ordered rules
+# and no duplicates. Installed as /usr/local/sbin/mealquest-firewall.
 set -eu
 
-port=8090
-match="-p tcp -m conntrack --ctorigdstport $port --ctdir ORIGINAL"
+tag="-m comment --comment mealquest-firewall"
+match="-m conntrack --ctorigdst 10.60.1.14 --ctorigdstport 8090 --ctdir ORIGINAL"
 
-iptables -C DOCKER-USER -s 10.60.1.33/32 $match -j RETURN 2>/dev/null ||
-	iptables -I DOCKER-USER 1 -s 10.60.1.33/32 $match -j RETURN
-iptables -C DOCKER-USER -s 10.60.1.14/32 $match -j RETURN 2>/dev/null ||
-	iptables -I DOCKER-USER 2 -s 10.60.1.14/32 $match -j RETURN
-iptables -C DOCKER-USER $match -j DROP 2>/dev/null ||
-	iptables -A DOCKER-USER $match -j DROP
+rules=$(iptables -w -S DOCKER-USER)
+printf '%s\n' "$rules" | while read -r _ chain spec; do
+	case " $spec " in
+	*" --comment mealquest-firewall "*) iptables -w -D "$chain" $spec ;;
+	esac
+done
+
+iptables -w -I DOCKER-USER 1 -s 10.60.1.33/32 $match $tag -j RETURN
+iptables -w -I DOCKER-USER 2 -s 10.60.1.14/32 $match $tag -j RETURN
+iptables -w -I DOCKER-USER 3 $match $tag -j DROP