Preventing some users from sending Internet mail in Exchange 2000/2003

In Exchange 5.5, it was reasonably easy to keep a user from sending or receiving SMTP mail. You just deleted their SMTP address and told the Internet Mail Service. However, with Exchange 2000 and 2003, all users require an SMTP address. You have to get a little trickier.

You need to define a recipient policy that applies to users that you don't want to have external mail addresses. You need to put those folks in a group, and you need to restrict that group from using the SMTP Connector(s). And, you need to make sure that the SMTP Connector recognizes those restrictions. See Microsoft KB 277872 for more information.

Sound simple? Well, Exchange guru Mark Fugatt has written an article that makes this a little more plain. He just updated it for Exchange 2003, but it still applies to Exchange 2000. The article is called Restricting Users From Sending and Receiving Internet Mail in Exchange 2003.