After upgrading Docker to version 24.0.4 iptables started to block access from container to host server where is running Postfix that I’m using as SMTP relay server for all running containers.
I’m allowing access to host via this configuration in docker-compose file:
extra_hosts: - "host.docker.internal:host-gateway"
And I see this block in system logs:
[Wed Jul 12 23:30:11 2023] IPTables-Dropped: IN=br-d9eaf06a2693 OUT= PHYSIN=veth8fc9819 MAC=02:42:47:ab:ef:30:02:42:ac:12:00:05:08:00 SRC=172.18.0.5 DST=172.17.0.1 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=8937 DF PROTO=TCP SPT=36926 DPT=25 WINDOW=64240 RES=0x00 SYN URGP=0
Was there some change in version 24.0.4 that changes the way how Docker is handling iptables?
Many thanks for eventual hints!