David Hrbáč wrote:
Well, I do not understand it now.
domain.tld has: mx 20 some_server2 mx 10 some_server1
The problem occurs on domain.tld == some_server1, which is a mail server. domain.tld does backups for some_server2.tld and vice versa.
so, domain.tld has: mx 20 some_server2.tld (so, they do backup in case our server is down) mx 10 domain.tld (this server. should deliver mails for domain.tld)
if some_server2.tld (which for we are doing mx backup as well) is down, our system keeps mails but does not deliver them.
BUT: (and that's the problem)
if one of us here on domain.tld wants to send an email to some_server2.tld, then this problem with 'loops back to me' occurs (since centos update).
so IMO, it is correct having
postmap -q some_server2.tld mysql:/etc/postfix/sql/transport returning smtp:some_server2.tld
and
postmap -q domain.tld mysql:/etc/postfix/sql/transport returning maildrop:
so, if mails for some_server2.tld are arriving at domain.tld, it tries to forward them via smtp to some_server2.tld which should be done via:
smtp inet n - n - 25 smtpd (from master.cf), AFAIK
and EVEN, if I REMOVE the mysql entry for smtp:some_server2.tld, so it should appear to postfix like every other domain in the world, postfix finds a loop back to itself.
And that's, what I don't understand.
This configuration was already working and productive.
thorsten.