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Is it possible to force SMTP mail picked up at an IIS 6.0 server to be sent directly to an Exchange 2003 server on an internal network?

Right now we have a third device in the middle which is being overloaded and delaying mail by 2 or 3 hours. I want to be able to skip the middle device and go directly from IIS to Exchange.

[Update] I should clarify the IIS server is also internal. I discovered that this 3rd device didn't get thrown into the mix until our new firewall was turned on last week (just hours before the holiday weekend started no less).

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up vote 1 down vote accepted

You can have an IIS 6.0 SMTP server send any incoming SMTP directly to another server for delivery. You're looking for at "Smart host".

Your "third device" is probably already configured as the "Smart host". Have a look in the properties for the SMTP server, on the "Delivery" tab, and click "Advanced". Specify the Exchange Server computer's name or IP there and be sure the "Attempt direct delivery before sending to smart host" is unchecked.

Obviously, verify (with TELNET or whatever) that the IIS 6 box can reach the Exchange Server computer's TCP port 25 by the name or IP you've specified above.

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Tried it and no go. I think we're having some other issue that popped up after our new firewall was turned on. But at least I know how to do the smart host. – user4417 Jul 10 '09 at 17:42
Glad I could help (at least sorta). You're not able to get TCP connectivity between the IIS box and Exchange on port 25, then? Bummer... – Evan Anderson Jul 10 '09 at 17:46

I assume that your website is configured to send to the local SMTP server?

You basically have two options.

  1. Configure your web app to use the SMTP server on the exchange server to send the emails.
  2. Configure the smarthost on the IIS SMTP server on the web server to direct all mail to the exchange server.
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given my choice I'd defintly tell the devs to use my exchange server instead of some 3rd system, However you want the mail to go to your edge - not your internal mailbox store. The reason for this is that should your website get spammed you won't have opened the floodgates – Jim B Jul 10 '09 at 17:07
On my next web app, I will try out sending directly to the Exchange server. In the mean time, I'm going to stick with #2. – user4417 Jul 10 '09 at 17:44

Add a hosts entry onto your IIS box, which points directly at the internal IP address of your exchange server. This should prevent it from doing an external DNS lookup and effectively bypass your firewall.

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