My installation is based on Debian 12 (Bookworm), with dockerized versions of Mailcow and Mailman 3 as described here:
https://docs.mailcow.email/third_party/mailman3/third_party-mailman3/
The server is a VM, running on Proxmox. Mailcow and Mailman are on the same VM.
It took a little time for me to setup things correctly, but mostly it seemed to work nicely. But a week ago it stopped working - I guess because I upgraded Mailcow to 2025-09b.
The problem is that Rspamd rejects all messages, coming from Mailman. Postfix receives mails coming to the mailing lists, but when Mailman tries to forward the mails to the subscribers, Postfix/Rspamd block all of them.
Postfix/Rspamd also block mails sent directly from Mailman, such as Welcome-messages - see an example below.
In Mailcow, I have under “Options” added 172.19.199.1/24 as a “Forwarding Host” with no spam filter. I hoped this would make Rspamd happy, but apparently not.
All messages, sent directly from Mailcow, pass various on-line tests of SSL, SPF, DKIM, and DMARC, and are accepted by other servers (Gmail, Hotmail etc.). All web-interfaces to Mailcow and Mailman work fine.
Messages to the various lists are archived, but not sent to the subscribers.
Any help appreciated :-)
Jesper
`Example of rspamd rejecting a welcome message from Mailman:
HFILTER_HOSTNAME_UNKNOWN (8.5)
DMARC_POLICY_QUARANTINE (8) [mydomain.dk : No valid SPF, No valid DKIM, quarantine]
R_SPF_FAIL (8) [-all]
HFILTER_HELO_BADIP (4.5) [172.19.199.4, 1]
VIOLATED_DIRECT_SPF (3.5)
FORGED_W_BAD_POLICY (3)
RDNS_NONE (2)
SUBJ_EXCESS_QP (1.2)
MIME_BASE64_TEXT_BOGUS (1)
MID_RHS_NOT_FQDN (0.5)
MIME_BASE64_TEXT (0.1)
RBL_SENDERSCORE_REPUT_9 (-1) [172.19.199.1:from]
MAILLIST (-0.2) [mailman]
MIME_GOOD (-0.1) [text/plain]
HAS_LIST_UNSUB (-0.01)
BAYES_HAM (-0.005474) [42.14%]
BCC (0)
FORGED_SENDER_MAILLIST (0)
ARC_SIGNED (0) [mydomain.dk:s=dkim:i=1]
TO_DOM_EQ_FROM_DOM (0)
FORGED_SENDER (0) [mylist-request@mydomain.dk, mylist-bounces@mydomain.dk]
RCPT_COUNT_ONE (0) [1]
FROM_NEQ_ENVFROM (0) [mylist-request@mydomain.dk, mylist-bounces@mydomain.dk]
MISSING_XM_UA (0)
R_DKIM_NA (0)
FROM_NO_DN (0)
ARC_NA (0)
TO_DN_ALL (0)
RCVD_COUNT_ZERO (0) [0]
TO_MATCH_ENVRCPT_ALL (0)
MIME_TRACE (0) [0:+]
PRECEDENCE_BULK (0)
`