Postconf Output ...
alias_maps = hash:/etc/aliases ... mailman_destination_recipient_limit = 1 ... relay_domains = lists.domain3.com relay_recipient_maps = hash:/var/lib/mailman/data/virtual-mailman ... transport_maps = hash:/etc/postfix/transport virtual_alias_domains = list.domain3.com
I'm confused about list.domain3.com vs. lists.domain3.com in relay_domains. You are correct, this was a typo in main.cf, and has been changed.
virtual_alias_maps = hash:/etc/postfix/virtual, hash:/var/www/domain3.com/domain3-virtual, hash:/var/lib/mailman/data/virtual-mailman ... Feb 25 16:48:48 bunsen postfix/virtual[3850]: 65F271C37A: to=MailingList@domain3.com, relay=virtual, delay=0.22, delays=0.2/0.02/0/0.01, >>dsn=5.1.1, status=bounced (unknown user: "MailingList@domain3.com")
It appears your mail is being mapped to MailingList@domain3.com via the mapping in /var/lib/mailman/data/virtual-mailman, and there is probably an alias for this address in /var/lib/mailman/data/aliases, but there is no hash:/var/lib/mailman/data/aliases in alias_maps.
/var/lib/mailman/data/virtual-mailman has the line: MailingList@lists.domain3.com MailingList
and /var/lib/mailman/data/aliases contains the line MailingList: "|/var/lib/mailman/mail/mailman post MailingList"
You are correct, the alias_maps line in /etc/postfix/main.cf does not reference hash:/var/lib/mailman/data/aliases I changed it to be: alias_maps = hash:/etc/aliases, hash:/var/lib/mailman/data/aliases
and now it appears to work.
It is not completely clear to me what's going on, but it looks like you have a Debian/Ubuntu package and are using postfix_to_mailman.py as a transport. I'd know more if I saw /etc/postfix/transport and /etc/postfix/master.cf.
If my thought above is correct, the issue is all lists should be in the same domain. See the FAQ at http://wiki.list.org/x/15564817 for more. I AM using Debian, but in setting up mailman, the FAQ makes postfix_to_mailman.py out to be a bad idea, so I abandoned it and tried to do things "The Right Way™". The alias_map was probably the core problem. Thanks for the help! Kevin Nowaczyk