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Microsoft KB Archive/251457

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Knowledge Base

XFOR: Connection Access Control Feature Does Not Block For Each Domain

Article ID: 251457

Article Last Modified on 2/21/2007


  • Microsoft Exchange 2000 Server Standard Edition

This article was previously published under Q251457


When you configure connection access to the Simple Mail Transfer Protocol (SMTP) server, the domain that you specify to be blocked may still be able to connect to the SMTP server. This connection occurs even though Domain Name System (DNS) reverse lookup is configured correctly.

For example, if you configure your SMTP server to block connections from the domain "" (by opening the properties of the virtual SMTP server, clicking the Access tab, clicking Connection, clicking All except the list below, and then adding the domain ""), a computer named may still be able to connect to your server.


This problem can occur if the blocked domain entry is not configured properly.


To work around this problem, make sure that the entry is formatted as follows:


For the example in the "Symptoms" section of this article, the correct entry is the following:


The following entry also works:


Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server.

Keywords: kbbug kbnofix KB251457