DOCUMENT:Q105130  30-OCT-1999  [pcmail]
TITLE   :SMTP: Err Msg: WARNING Incoming SMTP Mail From Unknown Host
PRODUCT :Microsoft Mail For PC Networks
PROD/VER:MS-DOS:2.1,3.0
OPER/SYS:
KEYWORDS:

======================================================================
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The information in this article applies to:

 - Microsoft Mail Gateway to SMTP, versions 2.1, 3.0 
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SYMPTOMS
========

Versions 2.1 and 3.0 of Microsoft Mail Gateway to SMTP may display the following
message in the SMTPGATE.LOG file, and/or the Gateway PC screen:

   [rx] HELO
   <time> WARNING Incoming SMTP mail from unknown host

   Note: Using the undocumented switch -CD with the SMTP gateway provides debug
   information on the gateway screen and log file when full logging is turned on
   with -GACSY and -LACSY command line options.

CAUSE
=====

This warning indicates that section 3.5 of RFC 821 (the "HELO" command is used
to identify the sending host) has been violated. The correct syntax should be:

   [rx] HELO hostname.domain

RESOLUTION
==========

No action is required. The SMTP Gateway will continue to process mail. The
message is merely for your information.

For more information refer to RFC 821.

Additional query words: 2.10 3.00 smtp warning helo

======================================================================
Keywords          :  
Technology        : kbMailSearch kbMailGateSearch kbZNotKeyword3 kbMailGateSMTP300 kbMailGateSMTP210
Version           : MS-DOS:2.1,3.0

=============================================================================

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