This tip might come in handy when you want to effectively block all incoming Internet mail traffic for a specific user or a specific group.

Before the advent of Exchange 2003, the solution to this question would have been to give the user or group a false e-mail address consisting of a non-resolvable SMTP domain name.

Now, with Exchange Server 2003, you can block all incoming Internet mail traffic for a specific user or group by forcing the user or group to only accept mail from authenticated users, thus blocking all (usually) anonymous Internet traffic.

To block all incoming Internet mail traffic for a specific group follow these steps:

1. Click "Start", point to "Programs", point to "Administrative Tools", and then click "Active Directory Users and Computers".
2. Right-click the distribution group, and then click "Properties".

3. Click the "Exchange General" tab.
4. Under "Message restrictions", click to select the "From authenticated users only" check box.

To block all incoming Internet mail traffic for a specific user follow these steps:

1. Click "Start", point to "Programs", point to "Administrative Tools", and then click "Active Directory Users and Computers".
2. Right-click the user account, and then click "Properties".

3. Click the "Exchange General" tab.
4. Click "Delivery Restrictions".

5. Under "Message restrictions", click to select the "From authenticated users only" check box.

After performing the above steps no anonymous traffic - i.e. SMTP traffic that was submitted to the store anonymously - will be allowed to reach the user or group.