To configure Microsoft's IIS SMTP (which is also the base for Microsoft Exchange 2000 and 2003) you can use about five different approaches.
As in most cases the IIS Management Interface doesn't provide all the options you need, you have to go on to more abstract ways.
When you use ADSI or WMI, you're actually editing the Metabase. It's very useful for writing scripts and other automated processes, but not so much for an initial config. In the last case you would rather want to use Notepad to edit the Metabase by hand.
The Metabase has a lot of settings (and combination of settings) which are not enabled in the IIS Management Interface. For example, you are able to set (a different) smarthost address per local domain by applying a different RouteAction. Or you could simply add a wildcard domain like *.com
But then there are always some "little" things that you still can't configure using all those approaches mentioned above. This is where the Registry comes in. The registry can set some additional start-up parameters on the SMTPSVC Service. This service is the main service for IIS SMTP and is also used by Exchange 2000 and 2003.
Because I couldn't find an exhaustive list of the available Registry settings anywhere on the net, I decided to present you one here. There might be some more. If so, please comment me on that and I'll add them to the list. Also, please tell me about any errors on this page.
Also know that all these settings work for IIS SMTP even though mosts sites tell you they only work for Exchange systems
The opinions expressed herein are my own personal opinions and do not represent
my employer's view in any way.