I'm trying to setup a mail server for my domain.org which I manage via dyndns' dynamic IP address.

I have setup the MX record in dyndns as
smtp.domain.org 10 domain.org and I created an alias smtp.domain.org
alias to domain.org.

Now, I come to my server /etc/postfix/main.cf and type
mydomain = smtp.domain.org and restart postfix.

If I do -

host -t mx domain.org - domain.org has no MX record

nslookup smtp.domain.org - Can't find smtp.domain.org.

But if I do -

host -t mx smtp.domain.org

I get reply smtp.domain.org mail is handled by 10 domain.org.

Can anyone tell me why my nslookup query is not resolving and how can I send mail as user@domain.org and not as user@smtp.domain.org?

Thanks.

ps: I can connect to domain.org on port 25.

I've never worked with dyndns. But if it's anything like bind9, I would say, based on what you wrote, that your MX record definition is backwards.

In bind, you put your domain first, THEN the record type, THEN the priority, THEN the host that handles the mail for the domain. But it looks like you put the host that handles your mail first, then the domain last.

Try switching those two, and see what happens.

Robert...

This issue has been resolved. All I needed to do was to add smtp.domain.org in the A record
(so smtp.domain.org points to my IP address) and then add MX record for domain.org as smtp.domain.org and then wait for a few minutes for the delegation to propagate across the Internet and done.

Thanks.