GNet Solutions » GNU/Linux Administration

I encountered a problem after joining my mail server to my Active Directory domain. The problem was that email was not being delivered, despite being able to successfully log into an account on the mail server. To start I logged in to the mail server to view the mail server log file, to find the following error:

tail /var/log

Feb 10 09:51:10 mailserver postfix/pipe⁹⁷³⁸: fatal: get_service_attr: unknown group: vmail

• While migrating the existing user information directory over to the Active Directory, I had to add a unique group name to the directory, the existing setup had a vmail user and a vmail group. This was to avoid a conflict between user and group identifier attributes, so I created a vmail user and a vmailgrp group. The problem was that I had not updated the group information in the postfix master configuration. I edited the /etc/postfix/master.cf file and changed the following line to the proper version:
  

  dovecot   unix  -       n       n       -       -       pipe
  flags=DROhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -f ${sender} -d ${user}@${nexthop}
  

  • Changed to:
    

    dovecot   unix  -       n       n       -       -       pipe
    flags=DROhu user=vmail:vmailgrp argv=/usr/lib/dovecot/deliver -f ${sender} -d ${user}@${nexthop}
    

• And finally reloaded the postfix configuration:
  

  postfix reload
  

This fixed the problem and mail immediate began to deliver properly.