I have had a postfix mail server up for quite a long time, running on Ubuntu Server x86_64. It is managing emails for multiple domain names. However, it has decided, seemingly arbitrarily, to stop accepting any extra-domain emails to a single domain.
If I mail a.com from a.com, it works, but the moment I mail to a.com from b.com (regardless of b.com being on the same server or not), it does not accept anything. I can't find any mention of the problem in error logs.
I have tried doing upgrades via apt-get
, but the problem has not been fixed. Rebooting or restarting the service does not fix it.
According to postconf -d | grep mail_version
, I'm on v2.9.6. I am using MySQL for the virtual user accounts. It is using dovecot v2.0.19.
Where should I start looking for where the problem came from? And how to prevent it from happening again?
Mail server for "a.com" unreachable for too long
bounce. I haven't received bounces on other mail servers I've tried...