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Q100709: SMTP: Err Msg: Network_read: Lost Network Connection

Article: Q100709
Product(s): Microsoft Mail For PC Networks
Version(s): MS-DOS:2.1,3.0
Operating System(s): 
Keyword(s): kbgraphxlinkcritical
Last Modified: 21-DEC-2001

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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
========

Microsoft Mail Gateway to SMTP may display this message:

  ERROR Network_read: Lost network connection
  SMTP_recv: system error

CAUSE
=====

This error message appears if:

- An error at the TCP or IP layer has occurred.

- The other host has gone down.

- The network between the Gateway computer and the other host has gone down.

- The other host may require that the PUSH flag be sent to push the SMTP packet
  up to the SMTP software, instead of remaining in the incoming buffer.

RESOLUTION
==========

You can test these possible causes by attempting to telnet to port 25 of the
smarthost and resending the message. This can usually be done by pressing
SPACEBAR and typing "25" (without the quotation marks) after the IP address on
the telnet command line.

If the error message appears frequently, check the network with a protocol
analyzer to determine the exact problem.

NOTE: Mail sent to IBM TCP/IP Version 2, Release 2 may result in this error
message if the PUSH flag is not set. FTP's pc/TCP automatically sets the PUSH
flag for outgoing packets. For Microsoft LAN Manager TCP/IP, please contact
Microsoft LAN Manager support for information on the availability to
automatically set the PUSH flag.

For Microsoft LAN Manager TCP/IP, ensure you are using version 2.2b (dated
2/1/94, 42,716 bytes) or later of the file TCPTSR.EXE. By default, TCPTSR.EXE is
found in the LANMAN.DOS\DRIVERS\PROTOCOL\TCPIP directory. Then add the parameter
ForcePushBit=1 to the [TCPIP] section of the PROTOCOL.INI file. It defaults to
0, but when it is set to 1, it causes the PUSH bit to be set on every outgoing
packet.

MORE INFORMATION
================

The following file is available for download from the Microsoft Download
Center:

  DownloadDownload Tcptsru.exe now
  (http://download.microsoft.com/download/pcmail/Utility/20/WIN/EN-US/Tcptsru.exe)

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.

Additional query words: 2.10 3.00 ERRMSG smart host push flag

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

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