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Prevent Exchange 2003 users from sending or receiving Internet mail

Exchange 2003 makes it easy to stop users from sending or receiving Internet mail. Once configured, they can only receive e-mail from other users in the same organization.

Some time ago I wrote about how to prevent Exchange 2000 users from sending mail to the Internet. Exchange Server...

2003 has functionality that now makes it easy to stop users from receiving mail sent to them from the Web as well. Once configured, users can only receive e-mail from other Exchange users in the same organization.

To make this happen, you first need to prevent Exchange users from sending e-mail to the Internet:

  1. Create a new mail-enabled group in Exchange that will be used to identify all users who have this restriction.

  2. Add any users to have incoming mail restricted to this group.

  3. Create a new SMTP Connector on the Exchange server and associate it with the appropriate Exchange server.

  4. Under the Delivery Restrictions tab of the connector's Properties, add the created group to the "Reject messages from:" section.

Now, you need to configure Exchange to prohibit users from receiving Internet-based e-mail:

  1. In Active Directory Users and Computers, go to the Properties page for the group (or individual user) for which you want to restrict e-mail access.

  2. Under the Exchange General tab, click Delivery Restrictions.

  3. Check the box labeled "Accept messages: From authenticated users only."

  4. Click OK to close all dialogs.
The "authenticated users" checkbox is new to Exchange Server 2003, and essentially limits mail traffic to only those who can successfully authenticate with the server (i.e., other Exchange users).

About the author: Serdar Yegulalp is editor of the Windows Power Users Newsletter and a regular contributor to


I created a security group and mail-enabled it. I assigned the users that I wanted to have only internal mail capability to this group and followed all the other steps in the tip. It didn't prevent outgoing OR incoming email to/from the Internet. Please advise.
—Pouya M.


I did a little more digging and found that there are a couple of Microsoft Knowledge Base articles that deal with the possibility that connector delivery restrictions might not work properly or connector restrictions might be disabled. It looks like both of these articles talk about the same registry setting, but talk about it in slightly different contexts.
—Serdar Yegulalp, tip author

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Related information from

  • Reference Center: Exchange permissions
  • Reference Center: Exchange user settings
  • Reference Center: Exchange Server 2003
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