I recently upgraded a remote server to CentOS-7.2, after which email stopped coming through. I suspect that this was probably due to the fact that I had started a version of dovecot installed some time ago. I found messages in /var/log/maillog like Jan 4 12:56:56 alfred postfix/lmtp[7612]: 20A662202B4: to=root@gayleard.eu, relay=alfred.gayleard.eu[private/dovecot-lmtp], delay=34272, delays=34272/0.16/0.01/0.05, dsn=4.3.0, status=deferred (host alfred.gayleard.eu[private/dovecot-lmtp] said: 451 4.3.0 root@gayleard.eu Invalid user settings. Refer to server log for more information. (in reply to RCPT TO command)) Googling for this, I found the suggestion that one should insert the following postmaster_address line in /etc/dovecot/conf.d/20-lmtp protocol lmtp { postmaster_address = postmaster@alfred.eu # Space separated list of plugins to load (default is global ail_plugins). mail_plugins = $mail_plugins sieve } (alfred.eu being the server's domain). This seems to have solved the problem, after re-starting dovecot.

I'm wondering if this was an issue that arose some time ago, and if so whether my solution was the recommended one?

-- Timothy Murphy
gayleard /at/ eircom.net School of Mathematics, Trinity College, Dublin