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Disabling checking for "my own hostname" in smtp connections to transports

By Oguz Yilmaz at 06/21/2010 - 07:58

Hi,

In some of my setups, I locate postfix as content filtering for smtp,
and before the original mail server.

internet -> postfix relay -> mail server

In cases of "myhostname=mail.mydomain.com" and also the hostname of
the mail server is "mail.mydomain.com" Postfix will give an error of
"greeted me with my own hostname" and bounce the e-mail with "loops
back to myself". Actually this is not a real loopback case.

Is it possible to disable checking for the corresponding hostname of
the transport?

Best Regards,

Oguz Yilmaz

Postfix 2.2.11

warning: host 10.15.0.10[10.15.0.10] greeted me with my own hostname
mail.mydomain.com
warning: host 10.15.0.10[10.15.0.10] replied to HELO/EHLO with my own
hostname mail.mydomain.com
6E0E31C3AC7: to=< ... at mydomain dot com>, relay=10.15.0.10[10.15.0.10],
delay=5, status=bounced (mail for 10.15.0.10 loops back to myself)

fallback_transport = maildrop
mydestination = localhost, localdomain, localhost.localdomain, $myhostname
mydomain = mydomain.com
myhostname = mail.mydomain.com
mynetworks = 127.0.0.1, 10.0.0.0/8
relay_domains = $mydestination, mydomain.com
smtp_host_lookup = native, dns
transport_maps = hash:/etc/postfix/transport

transport:
mydomain.com smtp:10.15.0.10
.mydomain.com smtp:10.15.0.10

Comments

Re: Disabling checking for "my own hostname" in smtp connections

By Wietse Venema at 06/21/2010 - 08:20

Oguz Yilmaz:

Use different myhostname settings for different MTA instances.
Each name should match the inet_interfaces setting of its MTA.

Wietse

Re: Disabling checking for "my own hostname" in smtp connections

By Oguz Yilmaz at 06/23/2010 - 14:47

For the case, mail server is not necessarily a Postfix. Yes it is a
workaround to find different myhostname variable setting then hostname
of the real mail server.

internet -> postfix relay -> mail server
mail.mydomain.com mail.mydomain.com

However, this needs a control:
- new myhostname should resolv to the same IP and the IP to the same
myhostname for a best practice antispam configuration.
- The customer may not have any other hostname defined in the DNS.
So, those cases will need a control and will not work seamlessly.

I just wanted to ask If Is there a way to disable "loops back to
myself" errors in a case which is not actually a real loop back.

Thanks Mr. Venema.

Best Regards,

Re: Disabling checking for "my own hostname" in smtp connections

By Victor Duchovni at 06/24/2010 - 13:20

Yes, by sending to a port other than port 25.