[Mailman-Users] Bounceback from Another List

[Jay A. Sekora]

> Thanks for the reply.  I have checked and double checked and
> List2 at example.com is not a member of list1 at example.com in the membership
> list.  Is there any other place I should check? From what I can tell
> that is "the" list of members.  [...]

> Do you think this could be an MTA problem (exim4)?  Has anybody seen an
> issue like this with MailMan + Exim4?

Two possibilities come to mind:

(1) The aliases were set up incorrectly, so that mail sent to
list1 at example.com actually gets injected into list2 instead (or
in addition).

(2) An individual member of list1 is forwarding their mail to
list2.  (Depending on the servers the mail crossed on its way, that
might be obvious in the headers.)

Any chance one of those is the case?

Jay