SMTP Properties
Load IIS MMC, (Control Panel -> Administrative Tools -> Internet Information Services)
Right click Default SMTP Virtual Server and choose Properties.
This screen shows the access tab.
Click Delivery Tab, and the Advanced button:
The Fully-qualified domain name can be 127.0.0.1, or the name of your computer. A dot is not required.
The Smart Host should be your ISP mail server.
Click OK when finished
Click the Access Tab, and the Connection button
This screen allows/disallows computers to access the server. Grant access to 127.0.0.1, and to the rest of your local network , if desired. Do not grant access to any other IP addresses/ranges.
Click OK when finished.
On Access Tab, Click Relay button
This screen allows/disallows relaying. This is very important disallowing relaying blocks potential spammers.
Select Only the list below. Do not add any IP addresses unless you know the risks regarding relaying and spammers.
Click OK when finished.
Click the OK button on the tabbed Properties screen. The remaining properties may be left with the default settings.
Next: Domains
Set up domains for the SMTP service. The service will intercept any emails for these domains and place the files in the folder: [drive]:\Inetpub\Mailroot\Drop