Use Integrated Windows Authentication to Authenticate Incoming Messages

To use Integrated Windows authentication to authenticate incoming messages:

1. Start System Manager:
   On the Start menu, point to Programs, point to Microsoft Exchange, and then click System Manager.
2. Navigate to the SMTP virtual server.
   1. Servers
   2. Server
   3. Protocols
   4. SMTP
   5. SMTP virtual servers
   6. SMTP virtual server
3. Right-click the SMTP virtual server, and then click Properties.
4. On the Access tab, under Access control, click Authentication.
5. In Authentication, select Integrated Windows authentication.