How to configure Windows Server 2008/IIS 7 to send email via an asp.net web application

IIS7 SMTP is the same as IIS6 SMTP. It wasn't updated, so even the management is done with IIS 6 Manager (even though everything else is IIS7). Edit the server properties and make sure that 127.0.0.1 is added as an approved relay IP address. That will allow it to work without authenticating as long as it's sent from the local machine.

Note: That was required with IIS6 too though so possibly you did this with the IIS6 server at some point in the past.

That's the only change I make to a new IIS SMTP server to ensure that it works from the local machine. (not counting spam settings like reverse and forward DNS entries)

I have come to the conclusion that the Microsoft SMTP service is not supported on the Core editions. I found this list:

http://www.microsoft.com/windowsserver2008/en/us/r2-differentiated-features.aspx

But such a list cannot be found for the core editions, bad documentation.

I'll install a third party SMTP service.