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<TITLE>RE: Help with smart host please</TITLE>
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<P><FONT SIZE=2>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). </FONT></P>
<P><FONT SIZE=2>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...</FONT></P>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Alan Fiebig [<A HREF="mailto:mailscanner@ELKNET.NET">mailto:mailscanner@ELKNET.NET</A>] </FONT>
<BR><FONT SIZE=2>Sent: Friday, September 19, 2003 5:12 PM</FONT>
<BR><FONT SIZE=2>To: MAILSCANNER@JISCMAIL.AC.UK</FONT>
<BR><FONT SIZE=2>Subject: Re: Help with smart host please</FONT>
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<P><FONT SIZE=2>No, sorry, I should have been clearer.</FONT>
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<P><FONT SIZE=2>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.</FONT></P>
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<P><FONT SIZE=2>For example, lets say that I have a message in /var/spool/mqueue that is to be delivered to 'sam@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.</FONT></P>
<P><FONT SIZE=2>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.</FONT></P>
<P><FONT SIZE=2>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.</FONT></P>
<P><FONT SIZE=2>Thanks,</FONT>
<BR><FONT SIZE=2>-Alan</FONT>
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<P><FONT SIZE=2>>I'm probably missing something here, but I'd just add the smarthost to </FONT>
<BR><FONT SIZE=2>>the DNS if you're timing out. Wouldn't that do it?</FONT>
<BR><FONT SIZE=2>></FONT>
<BR><FONT SIZE=2>>...Kevin</FONT>
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