XFOR: Routing Restrictions May Not Work with Some Antivirus Solutions (254214)


The information in this article applies to:

  • Microsoft Exchange Server 5.5
This article was previously published under Q254214

SYMPTOMS

Routing restrictions may not work after you install Simple Mail Transfer Protocol (SMTP) antivirus software.

When you install SMTP antivirus software, the installation places the Exchange Server Internet Mail Service behind an antivirus 'firewall,' as illustrated in the following diagram:

(Internet) ----> (SMTP Virus Scanner) ----> (Exchange Server Internet Mail Service)

In this configuration, the routing restrictions, specifically the options that require a specific IP address or range of IP addresses, may no longer work.

NOTE: Routing restrictions are created on the Routing tab of the Internet Mail Service. A routing restriction is a unit of criteria to allow or restrict incoming SMTP mail.

CAUSE

When an Exchange Server computer running the Internet Mail Service is placed behind an SMTP virus scanner or virus firewall, as illustrated in the diagram in the "Symptoms" section of this article, then the Internet Mail Service actually only accepts connections from the antivirus software. Thus, when the Internet Mail Service processes the message, it records the source computer as 127.0.0.1 (the local host), so the Internet Mail Service never sees all of the other Internet IP addresses.

WORKAROUND

To work around this problem, make sure that the first SMTP daemon, the antivirus firewall, is capable of advanced restrictions.

STATUS

This behavior is by design.

MORE INFORMATION

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

173903 XFOR: Changing the TCP Port Used for SMTP Mail

This article describes how to configure the Exchange Server Internet Mail Service and an SMTP based virus scanner to work together on the same computer. After you follow the instructions in this article, each product runs on a different port.

For antivirus features, please contact your antivirus software vendor.
Modification Type:MinorLast Reviewed:4/28/2005
Keywords:kbprb KB254214
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