Hi,
I have a problem with my Mailman 3-setup. The symptom is that postfix rejects non-existing addresses for my list domains with
<adr@example.com>: mail for example.com loops back to myself
What I guess happens happens is that postfix for some reason accepts the mail as it is for a relay domain and finds that it is not deliverable locally as the address does not exist locally and then tries to relay it on to the appropriate MX server, which is itself and then fails and generates a bounce message.
This is a bit annoying as I have set up postfix to only accept valid addresses. I have set the transport_maps, local_recipient_maps and relay_domains to the files generated by MM3. I run an older version of MM3 (3.0) but prefer to fix this without upgrading as upgrading is a relatively big undertaking.
This is mostly a backscatter problem for spam I guess.
Any ideas of very simple and easy to forget things that I've probably missed?
Cheers // David
Were you ever able to solve this problem? I'm having exactly the same issue with GNU Mailman 3.3.9 (Tom Sawyer), and I can't work out what I should be doing. Thanks!
On Thu, Jan 11, 2024 at 7:30 AM <simonjwiles@gmail.com> wrote:
Were you ever able to solve this problem? I'm having exactly the same issue with GNU Mailman 3.3.9 (Tom Sawyer), and I can't work out what I should be doing. Thanks!
The standard configuration is detailed at: https://docs.mailman3.org/en/latest/install/virtualenv.html#setup-mta For *unusual* configurations, you can look at this page: https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.ht..., especially https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.ht...
-- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254 7 3200 0004/+254 7 2274 3223 "Oh, the cruft.", egrep -v '^$|^.*#' ¯\_(ツ)_/¯ :-) [How to ask smart questions: http://www.catb.org/~esr/faqs/smart-questions.html]
Thank you, yes, I've read all the documentation. My system works properly (transport_maps, local_recipient_maps, relay_domains), I don't think it's an unusual configuration at all. Mail and all functions for configured lists work properly (I have > 100 lists on this server), I just have the same issue as the OP -- mail to <address-does-not-exist@lists.my-domain.tld> is bounced with the message "mail for lists.my-domain.tld loops back to myself". One common example is <list-used-to-exist-bounces@lists.my-domain.tld>.
Postfix relay_domains points to regexp: /path/to/mailman/postfix_domains, and postfix_domains contains the line /^lists\.my-domain\.tld$/ lists.my-domain.tld (and mail for legitimate lists is routed correctly via lmtp), so I'm not sure what's not right.
Grateful for any insight you can offer! Thanks!
On 1/11/24 10:31, simonjwiles@gmail.com wrote:
Thank you, yes, I've read all the documentation. My system works properly (
transport_maps,local_recipient_maps,relay_domains), I don't think it's an unusual configuration at all.
I think the issue is setting relay_domains in postfix. I don't think this is necessary.
Try removing that setting from postfix and see if mail to Mailman still works and mail to non-existent addresses is rejected for a more appropriate reason.
On the other hand, why is rejection for "Loops back to myself" a problem. Granted it's not a very informative message, but the mail should be rejected anyway.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
Thank you for your message!
The docs say "[s]etting relay_domains means Postfix will start to accept mail for newly added domains even if they are not part of mydestination" -- are you suggesting I should put my list (sub)domains in mydestination in my postfix config instead? Otherwise, as I understand it (big caveat!), that's exactly what *does* cause this problem; postfix doesn't think it handles the domain so it routes it externally but the MX records point it back to itself.
I'm wary of borking a working system that's so busy, so I'll see if I can set up an environment to test this.
I would prefer to reject mail appropriately with the correct code if possible.
simonjwiles@gmail.com writes:
Grateful for any insight you can offer! Thanks!
Have you asked Postfix channels? I don't think this is a Mailman problem, and they would recognize the issue faster than we do.
The first thing I would do is grep /path/to/mailman/var/data/postfix_lmtp for the looping address. If it's not in there, then Mailman is not involved in the loop.
I'm pretty sure that what's happening is the domain is recognized because it's in relay_domains, the transport maps are consulted, the address lookup fails, the transport defaults to relay_transport, which defaults to relay, which is in fact smptd, which recognizes a loop because the source and next-hop are both self. Voila!
From the ADDRESS_CLASS_README:
Valid recipient addresses for [relay_domains] are listed with the
relay_recipient_maps parameter. The Postfix SMTP server rejects
invalid recipients with "User unknown in relay recipient table".
If this parameter value is empty, the Postfix SMTP server accepts
all recipients for domains listed with the relay_domains
parameter. [Ie, you're an MX for those domains.]I guess
relay_recipient_maps = hash:/path/to/mailman/var/data/postfix_lmtp
will fix this problem assuming the error message above is acceptable. I can't guarantee it won't cause other problems, though, depending on whether your host provides other services to those domains.
Steve
participants (5)
-
David Krantz -
Mark Sapiro -
Odhiambo Washington -
simonjwiles＠gmail.com -
Stephen J. Turnbull