XFOR: Disabling Outbound ESMTP

ID: Q194132

The information in this article applies to:

Microsoft Exchange Server, version 5.5

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.

SUMMARY

Under specific circumstances, dependent on a customer's messaging environment, network, and/or topology, it may be necessary to disable sending the EHLO command to a remote host from the Exchange Server 5.5 Internet Mail Service. If an Exchange Server 5.5 Internet Mail Service connects to another mail host, which is functioning properly, the mail host will send back the following banner:


   20 <host fully qualified domain name> Server SMTP ready at Thu, 27 Aug
   1998 10:57:09 +0100

When sending the EHLO command (sent by default in Exchange Server 5.5), to a mail host that either doesn't have support for the command, or is disabled, you will receive the following message:


   ehlo Microsoft.com
   550 Unknown command 'ehlo

To disable sending the EHLO command by default, and send a standard Helo command instead, a registry change must be made. To do so, follow these steps:

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. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

Start Registry Editor (Regedt32.exe).

Locate the following key in the registry:
```
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIMC
   \Parameters
  
```
NOTE: The above registry key is one path; it has been wrapped for readability.

On the Edit menu, click Add Value, and then add the following registry value:


      Value Name: "DisableOutboundESMTP"
      Data Type:  "REG_DWORD"
      Value:      1

Quit Registry Editor.

Stop and restart the Internet Mail Service.

At this point, when the Exchange Server Internet Mail Service initiates a connection to any other SMTP or ESMTP mail host, it will only send the Helo command.

Keywords :
Version : WINDOWS:5.5
Platform : WINDOWS
Issue type : kbinfo