[Resolved] Send all mail to Smart Host not working.

[ridshack]

Interesting information –

When setting the sendmail.cf smart host to the fully qualified domain name I get a different error back in the Scalix email account attempting to send outbound email.

The original message was received at Mon, 29 Jan 2007 01:37:05 -0600
from localhost.localdomain [127.0.0.1]

----- The following addresses had permanent fatal errors -----
<jsmith@aoutbounddomain.com>
(reason: 553 5.3.5 system config error)

----- Transcript of session follows -----
553 5.3.5 assp.validdomain.org. config error: mail loops back to me (MX problem?)
554 5.3.5 Local configuration error

Scalix thinks the address loops back to itself…. I found this to be a common sendmail issue but not sure how it all ties in with Scalix.

When I do a telnet from the Scalix server to the same address set in the sendmail.cf it works fine.

[root@mail ~]# telnet assp.validdomain.org 25
Trying 10.1.1.246...
Connected to assp.validdomain.org (10.1.1.246).
Escape character is '^]'.
220 mail.validdomain.org ESMTP Postfix

I am running a fresh install of Redhat ES 4 with Scalix 11. The smart host is installed on a different server then Scalix and is using Postfix.

[ridshack]

k Normally when sendmail connects to a host via
> SMTP, it checks to make sure that this isn't acci-
> dently the same host name as might happen if send-
> mail is misconfigured or if a long-haul network
> interface is set in loopback mode. This flag dis-
> ables the loopback check. It should only be used
> under very unusual circumstances.

I found that Sendmail checks to make sure the Smart Host MTA is not the same as its own to avoid loops. My names where the same between the two servers mail.validdomain.org.

I changed the smart host MTA and bingo! It is now working.