Microsoft KB Archive/186142

= XFOR: Internet Mail Server Does Not Send FQDN When Using HELO or EHLO =

Article ID: 186142

Article Last Modified on 9/22/2005

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APPLIES TO


 * Microsoft Commercial Internet System 1.0 Service Pack 2

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This article was previously published under Q186142



IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.



SYMPTOMS
Microsoft Commercial Internet System Internet Mail Service does not use the Fully Qualified Domain Name (FQDN) when submitting the SMTP HELO or EHLO commands to a remote server. This causes mail to be rejected by SMTP hosts that require reverse look-up.

NOTE: The following is an example of the non deliverable report that is generated:

--Transcript of session follows --- postmaster@company.net

501 EHLO requires a valid host name as operand: 'SERVER' rejected from host-

209-214-184-154.clt.bellsouth.net[209.214.184.154]: hostname must contain

a

'.'.



CAUSE
Internet Mail Server was not originally designed to send the FQDN. Although it does not violate RFC 821, it does conflict with many of the current anti- spoofing or anti-spamming systems that do a reverse look-up to validate this information for the sender.



RESOLUTION
WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

The fix mentioned below allows the use of a new registry parameter called FQDN that must be created under the following registry path:

HKLM\System\CurrentControlSet\Services\SMTPSVC\Parameters\

FQDN is a string value, so use the data type REG_SZ when you create the value. Enter the desired string for the FQDN.

Example: mail1.company.com

To resolve this problem, obtain the fix listed below:

This fix should have the following time stamp and version: 05/15/98 06:42p               399,120 smtpsvc.dll(Alpha) 05.00.7747

05/15/98 06:42p               263,072 smtpsvc.dll(Intel) 05.00.7747



STATUS
Microsoft has confirmed this to be a problem in Microsoft Commercial Internet System version 1.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.



MORE INFORMATION
If a valid value from the FQDN registry parameter is received, then this string value is used as the FQDN. If this does not exist, is not a string, or is zero length, then the host name is received by calling gethostname. If this fails (or is zero length), then the host name is set to the computer name. Finally, when there is a host name, the default domain is concatenated to generate an FQDN. This is then used on outbound connections when the HELO or EHLO Commands are generated.

Additional query words: prodmcis1 internet mail service prodIMS

Keywords: kbbug kbfix kbqfe kbhotfixserver KB186142

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