Postfix-Mailman "Recipient address rejected: User unknown in local recipient table"

Question

I assume the error is an issue with my postfix configuration. I've followed the steps in the instructions here to set up apache/postfix/mailman.

Real domain replaced with mydomain.com I've created a default mail list called mailman. When I send an email to [email protected] I get the error "Recipient address rejected: User unknown in local recipient table" in the mail.log.

550 5.1.1 <[email protected]>: Recipient address rejected: User unknown in local recipient table; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<mail-wi0-f174.google.com>

Excerpts from my postfix/main.cf:

myhostname = mydomain.com
mydestination = mydomain.com, localhost
inet_protocols = ipv4
relay_domains = mydomain.com
transport_maps = hash:/etc/postfix/transport
mailman_destination_recipient_limit = 1

Excerpts from /etc/postfix/transport

mydomain.com mailman:

Excerpt from postfix/master.cf

mailman   unix  -       n       n       -       -       pipe
  flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
  ${nexthop} ${user}

If I understand correctly how it should work...

1. mail comes in to mydomain.com
2. postfix validates the hostname against $myhostname
3. postfix finds mydomain.com under relay_domains
4. postfix relays the mail to the transport listed under transport_maps
5. failing here? the postmap table finds that [email protected] matches mydomain.com
6. postmap directs the mail to the mailman: transport defined in master.cf
7. the transport mailman: calls postfix-to-mailman.py, and mailman handles the mail

Answer 1

I don't know if this qualifies as an answer but after doing much more reading I came to this conclusion, and hopefully it helps someone else.

There are two ways to configure mailman with postfix. 1. Use the transport maps, as I was trying above 2. Alias mapping

From my reading, method 1 which uses 'postfix-to-mailman.py' is unofficial and not well supported. So I attempted to try method 2 and it worked!

Steps: Remove transport method

Remove lines from postfix/main.cf:

relay_domains = mydomain.com
transport_maps = hash:/etc/postfix/transport
mailman_destination_recipient_limit = 1

Remove lines from master.cf:

mailman   unix  -       n       n       -       -       pipe
   flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
   ${nexthop} ${user}

Remove any lines from /etc/postfix/transport:

lists.domain.com   mailman:

Switch to alias method

Uncomment line in /usr/lib/mailman/Mailman/mm_cfg.py

MTA = 'Postfix'

Copy alias file to mailman directory and run genaliases to create the alias db

sudo cp /etc/aliases /var/lib/mailman/data/aliases
sudo /usr/lib/mailman/bin/genaliases
sudo chomod g+w /var/lib/mailman/data/aliases.db

Update alias_maps in postfix/main.cf to point to new alias file

alias_maps = hash:/etc/aliases,hash:/var/lib/mailman/data/aliases
alias_database = hash:/etc/aliases, hash:/var/lib/mailman/data/aliases

Reload and restart

sudo /etc/init.d/postfix reload
sudo service postfix restart