Article ID: 833799 - View products that this article applies to.
This article describes how to create a Microsoft Outlook profile file that you can use to configure static communication ports in Microsoft Office Outlook 2007 and in Microsoft Office Outlook 2003. The static ports are used to connect to a Microsoft Exchange server. This procedure can be used to work around the problem that prevents Outlook from communicating through port 135 to prompt the End Point Mapper where to find the Exchange server.
Both Microsoft Outlook and Microsoft Exchange use the remote procedure call (RPC) protocol to communicate. When an Exchange server starts, each of its services are dynamically assigned to a port. The port number that each Exchange server listens on can change every time that the Exchange server starts. When an Exchange server starts, it registers itself with the End Point Mapper, and prompts the End Point Mapper to assign it a port number.
When Outlook starts, it must determine the port where the TCP/IP end-point on the Exchange server has been assigned. To find the port number that Outlook must communicate with, Outlook contacts the Exchange server's End Point Mapper that tracks what service is listening on what port. The End Point Mapper always listens on port 135.
Recently, a problem has been discovered in the part of the RPC functionality that deals with e-mail message exchange over TCP/IP. The vulnerability results because of incorrect handling of malformed e-mail messages. This particular vulnerability affects the RPC Endpoint Mapper process. The End Point Mapper listens on TCP/IP port 135. Therefore, Outlook cannot use port 135 to prompt the End Point Mapper where to find the Exchange server.
To work around this problem, you can configure Outlook 2003 and your Exchange server to communicate through a predetermined set of identical communication ports. Additionally, this configuration gives you access to your Exchange server over the Internet if port 135 is blocked, and it will make sure that you are not vulnerable to the problems that are associated with an un-patched RPC End Point Mapper. This change in configuration is similar to RPC over HTTP communication between Outlook 2003 and Microsoft Exchange 2003, and it will improve the performance and the network round-trip time to establish a connection.
Configure static communication ports in Outlook 2003To configure Outlook 2003 to communicate on static ports, use the configuration settings in step 2 of the following steps to create an Outlook profile file (.PRF). You can then import this file with the fixed port settings in your default profile in Outlook 2003. This configures your Exchange account in Outlook to only communicate over these ports. To do this, follow these steps.
Note Changing the RCP over HTTP port mappings should only be done under specific circumstances with guidance from your systems administrator. Also, doing so may interfere with future revisions of this product and may hinder your ability to connect to the Exchange server with RPC over HTTP.
Configure static communication ports in ExchangeFor additional information about how to configure fixed communication ports on your Microsoft Exchange server, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/270836/ )Exchange 2000 and Exchange 2003 static port mappings
For additional information about the vulnerability in the RPC Endpoint Mapper, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/331953/ )MS03-010: Flaw in RPC Endpoint Mapper could allow denial of service attacks
Article ID: 833799 - Last Review: March 14, 2007 - Revision: 2.4
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