I have two courier-servers (testing purposes) running: mailtest.mydomain.com and mailtest2.mydomain.com The first hosts a mail account, the second one relays any mail to the first. Both machine's have the same MX-prefernce.
Occasionaly, I receive the following error: <<< configuration error: mail loops back to myself (MX problem).
I'm not sure why to be honest. Any ideas?
Study the following rule religiously:
Every DNS hostname that has either an MX or an A record that resolves to any IP address assigned to this server must be listed either in locals, or have an explicit entry in esmtproutes telling the server where mail for this domain goes.
In all cases, all the hostnames must also be listed in esmtpacceptmailfor.
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