I have in the postfix conf:

relayhost = my.internal.relay.example.org

All the mails transit through this relay. by default, postfix will try to do a MX lookup on my.internal.relay.example.org

Why ?

It's not the purpose of MX record. I just want to send through this host, not to the domain.

I know how to fix it (with [] or postfix config). postfix manuals says how to change the behaviour but not the reason.


For SMTP servers delivering mail to MX records comes very naturally.

By also supporting a MX record in the relayhost setting you also automatically get the native fall-over, load balancing and redundancy that MX records can provide.

Supporting only a single ip-address or hostname is all fine and dandy when you only have a single relay machine.
When you want to prevent a single point of failure setting up two or more machines using MX records is fairly trivial way to achieve redundancy and HA, compared to setting up a cluster with either fail-over and/or a load balancer on that relayhost ip-address/hostname. Using MX records is probably also easier than adding a failover support in Postfix with for instance a optional setting for a backup_relayhost.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.