DOCUMENT:Q254214  03-MAR-2000  [exchange]
TITLE   :XFOR: Routing Restrictions Don't Work w Some Antivirus Solutions
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.5
OPER/SYS:
KEYWORDS:exc55

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The information in this article applies to:

 - Microsoft Exchange Server, version 5.5 
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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:

   Q173903 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.

Additional query words: antivirus norton symantec port 25 av

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Keywords          : exc55 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : winnt:5.5
Issue type        : kbprb

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