Hi.

I moved Mailman instance to a machine running Debian Bullseye last week.

Ran into an issue with the Exim transport from this doc:

https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.ht...

The issue I ran into was that Exim wasn't able to resolve localhost in order to connect to the LMTP listener.

I changed VPS provider at the same time (moved from Bytemark to Gandi) so not sure if they were doing anything different with DNS, but by default Exim doesn't use standard libraries to lookup hosts:

https://www.exim.org/exim-html-current/doc/html/spec_html/ch-the_dnslookup_r...

I solved the issue by using the following configuration on the Mailman router:

# /etc/exim4/conf.d/transport/55_mm3_transport mailman3_transport: driver = smtp protocol = lmtp allow_localhost gethostbyname hosts = localhost port = MM3_LMTP_PORT rcpt_include_affixes = true

I haven't defined the lmtp settings at all in mailman.cfg meaning they are using the default settings of 127.0.0.1:8024.

Is this the best modification to make to the Exim config or should I go an alternative route?

Thanks. Andrew.