I have been trying to make mailcow work on Alpine, and it kind of works but this container refuses to connect to internet (update.sh didnt help)
docker version: 26.1.5 API: 1.45
docker compose version: 2.27.0
iptables INPUT and DOCKER-USER chains:
Chain INPUT (policy DROP 435K packets, 48M bytes)
pkts bytes target prot opt in out source destination
7555 8843K ACCEPT all -- lo any anywhere anywhere
1335K 2980M ACCEPT all -- any any anywhere anywhere state RELATED,ESTABLISHED
3461 202K ACCEPT tcp -- eth0 any anywhere anywhere tcp dpt:https
464 35893 ACCEPT tcp -- eth0 any anywhere anywhere tcp dpt:ssh
Chain DOCKER-USER (1 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- lo any anywhere anywhere
1142 124K ACCEPT all -- eth0 any anywhere anywhere ctstate RELATED,ESTABLISHED
16 800 ACCEPT tcp -- eth0 any anywhere anywhere multiport dports smtp,pop3,imap2,submissions,submission,imaps,pop3s,sieve
15 708 DROP all -- eth0 any anywhere anywhere
41609 20M RETURN all -- any any anywhere anywhere
inside the container dig fails:
dig +short +timeout=2 +tries=1 hub.docker.com @127.0.0.1
;; communications error to 127.0.0.1#53: timed out
;; no servers could be reached
tested the same setup (mailcow.conf, iptables setup) on debian machine, container was able to pass the health check