Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine whether the port value for the Microsoft Exchange System Attendant directory referral port has been manually overridden:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeSA\Parameters\TCP/IP Port

If the Exchange Server Analyzer finds that TCP/IP Port is present and configured, a non-default configuration message is displayed.

The most common reason that this value is configured is to enable MAPI clients to connect to an Exchange server that is on the other side of a firewall. This scenario involves opening multiple ports on a firewall to enable Microsoft Office Outlook® 2003 clients to connect using MAPI to an Exchange server, typically over the Internet. This configuration is supported. For more information about configuring MAPI clients to connect to Exchange through a firewall, see the Microsoft Knowledge Base article 270836, "Exchange 2000 and Exchange 2003 Static Port Mappings" ( If you are not using this scenario, you should remove the registry key.

The recommended deployment for using Outlook in MAPI Mode to connect to an Exchange server over the Internet is to use the remote procedure call (RPC) over Hypertext Transfer Protocol (HTTP) features found in Microsoft Windows Server™ 2003, Exchange Server 2003, Outlook 2003, and Windows® XP Professional. MAPI Mode was formerly referred to as Corporate or Workgroup mode.

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

To remove the TCP/IP port registry value

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\System\CurrentControlSet\Services\MSExchangeSA\Parameters

  3. Delete the registry value called TCP/IP Port.

  4. Close the registry editor, and restart the Microsoft Exchange System Attendant service.

To deploy RPC over HTTPS

  1. Review Exchange Server 2003 RPC over HTTP Deployment Scenarios (

  2. Review the Knowledge Base article 833401, "How to configure RPC over HTTP on a single server in Exchange Server 2003" (

  3. Review the Knowledge Base article 827330, "How to troubleshoot client RPC over HTTP connection issues in Office Outlook 2003" (

  4. Review the Microsoft Support WebCast, "Using Microsoft Exchange over the Internet (RPC/HTTP) with Microsoft Office Outlook 2003" (

Before you edit the registry, and for information about how to edit the registry, see the Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (