Install the SMTP virtual server that is part of IIS.
- You will need your Windows installation CD.
- Use Add or Remove Programs in the Windows Control Panel to launch Add/Remove Windows Components.
- Select Internet Information Services (IIS) and then click Details.
- Check SMTP Service and then click OK.
- The installation process will prompt you for your Windows CD and will install the SMTP virtual server.
After installing the SMTP server (also reboot), configure it by following these steps:
- In the Control Panel, choose Administrative Tools, and then choose Internet Information Services.
- Open the node for your computer, right-click the Default SMTP Virtual Server node and choose Properties.
- In the Access tab, click Connection.
- Select Only the list below, click Add and add the IP 127.0.0.1. This restricts connections to just the local computer, i.e., localhost. Close the Connection dialog box.
- Click Relay and repeat Step 5 to allow only localhost to relay through this server.
In your firewall or router (or both), close incoming port 25. This is an important security measure that will prevent spammers from finding your SMTP server and using it to relay spam.