Help with smart host please

[Jason Burzenski]

I've had similar problems in the past using sendmail mailertable (which
basically does the same thing as smarthost except on a per domain basis).
The outcome is the same, even when I have the domains routing to the IP
addresses of the internal mail destinations.  The problem is, sendmail wants
to check if the MX record is valid even if you are telling it to route mail
regardless of DNS.  I've even had sendmail re-write the to: field based on
the results from DNS (caused havoc on the internal boxes).

Temp solution: I have an internal dns box setup with no MX information for
the domains I am routing.  Sendmail gets a response back indicating that
there is no MX records available for the domains (not that the domains don't
exist, otherwise it will try to lookup recursively) and forwards the
message, in-tact to the destination host.  No a pretty solution, not a clean
solution, not a good solution but its working...

-----Original Message-----
From: Alan Fiebig [mailto:mailscanner at ELKNET.NET]
Sent: Friday, September 19, 2003 5:12 PM
To: MAILSCANNER at JISCMAIL.AC.UK
Subject: Re: Help with smart host please


No, sorry, I should have been clearer.

Its not that my MS server is timing out on DNS lookups of my smarthost, its
that sendmail on my MS server is still bothering to lookup the final
destination.


For example, lets say that I have a message in /var/spool/mqueue that is to
be delivered to 'sam at cucumber.org'. As I have sendmail on my MS server
configured to use a smarthost, sendmail should then just blindly forward
that message to the smarthost (talia.elknet.net) and let the smarthost
firgure out how to get the message to the 'cucumber.org' smtp server.

But, that's not what's happening. Sendmail on my MS server instead is
bothering to do a DNS lookup on 'cucumber.org' BEFORE sending it on to the
smarthost. If the DNS lookup fails or timesout, then sendmail deferrs the
delivery to the smarthost and keeps the message in the queue. Sendmail WILL
NOT forward the message on to the smarthost until AFTER it has successfully
looked up the destination domain, then it sends it on to the smarthost.

When using a smarthost, my outbound queue should be virtually empty. MS
should place a message into the mqueue, and within seconds sendmail should
grab it and send it on to the smarthost. But that's not happening, instead,
only the message that snedmail successfully does a DNS lookup on are being
forwarded, the rest are sitting in the queue deferred until a future time,
when sendmail will again try and do a DNS lookup.

Thanks,
-Alan


>I'm probably missing something here, but I'd just add the smarthost to
>the DNS if you're timing out.  Wouldn't that do it?
>
>...Kevin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.mailscanner.info/pipermail/mailscanner/attachments/20030919/ec80f6c8/attachment.html