Hi,
I've been running a dockerized mailman3 server for several years with
DMARC mitigation set to conditional. I use the 0.4 version of the
mailman3 docker images.
Recently I had to update my network configuration to prevent spammers
using IPv6 to circumvent the no-relay configuration of my exim4 server.
Previously, I had both exim4 and mailman3 on the same docker bridge
172.19.0.0/16 and exim4 was configured to relay email from this network
only. There was no problem regarding DMARC mitigation : most of the
emails didn't need to be altered.
Now I have added an internal docker network 172.29.0.0/16 and configured
exim4 to relay from this internal network only. Since this network is
not accessible from the host, IPv6 spammers are blocked (*).
But since this modification mailman alters every emails with DMARC
mitigation.
Any hint how to debug this issue?
Thanks in advance,
_g.
(*) With IPv6 incoming connexions mailman docker replaces the client
address with the IPv4 address of the host one the bridge network:
172.19.0.1.
