Firstly the setup is a little different. Once you have it installed select properties for the smtp service from the IIS MMC. On the General tab select advanced and on the next screen choose edit to set the incoming port to something other than 25. Select General->Connection and verify that the outgoing port is set to 25. Select Delivery->Advanced and enter the fqdn (fully qualified domain name) in the appropriate field.

So I installed the service, made the port change, set my fqdn, and tested by sending myself an email from a web program using CDONTS. Worked great. Patted myself on the back and rode off into the sunset to live happily ever after.

Only thing was that the first time a client tried to use CDONTS it failed which was about 15 minutes later. So I tested again from his web server by sending another message to my email address. That worked. Then I tried to send to one of my off-my-server addresses which failed. Basically I could send an email to any domain defined in my hosts file.

I won't bore you with what I did for the next humiliatingly long time but just give you what I finally did to make everything work.

Firstly, I had to change the name of the server so that it was the same as the fqdn. I should have done this anyway but hadn't so I didn't really mind. I did try the masquerade setting on the on smtp service and I did try changing the name of the service as well as several other things.

Secondly, I had to run MS DNS service as a cache only dns server. I assumed that the SMTP server would get its dns from the general dns settings for the server's connection. That apparently is not true if IMAIL is installed.

One I made these changes both IMAIL and MS SMTP get along just fine.

Interestingly it appears that if you don't have IMAIL running then MS SMTP works under about any kind of conditions with any kind of server name and no apparent need for MS DNS. Or at least that's what I found on my server.