Folks
I'm noticing that two installations of Postfix:
version 3.4.13-0ubuntu1.2) on Ubuntu 20.04.5
version 3.6.4-1ubuntu1 on Ubuntu 22.04.1
are both failing to use the MX value for outgoing
mail. Specifically, sending mail to any...@sonic.net (forget that no
such account exists) should be connecting to the mail exchange at
mailin-01.mx.sonic.net or mailin-02.mx.sonic.net and NOT to
sonic.net. The contents of the /var/log/maillog show the attempted
connects to sonic.net which obviously fail, since "sonic.net" is not
a mail server.
In both cases, I'm running BIND9 to serve a local network, and am
using systemd's resolvconf. In both cases, also, both "dig mx
sonic.net" and "host -mx sonic.net" produce the correct MX values.
I have been unable to figure out what knob or switch or setting might
be causing this behavior; any pointers or clues would be
appreciated. I can supply copies of configuration files if someone
wants to dig further.
Thanks
David
