In this post we will configure the SMTP virtual server in Windows Server 2008 R2 to relay mail using Google.

Open IIS 6.0 Manager;

Right click the SMTP server and choose Properties;

Set your preferences for access and connection control and also relay restrictions.

Next choose the Delivery tab ~ Outbound Security;

Select Basic Authentication and enter your Google user name and password, then check “TLS encryption” and click OK.

Click on Outbound Connections;

Enter 587 as the TCP port, click OK.

Click on Advanced;

Enter smtp.google.com as the Smart host, click OK.

Click OK and you’re done.