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Q217351: PRB: DCOM Port Range Configuration Problems

Article: Q217351
Product(s): Microsoft Windows NT
Version(s): 4.0
Operating System(s): 
Keyword(s): kbOSWinNT400 kbOSWinNT400sp4 kbDSupport
Last Modified: 11-JUN-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0 
- Microsoft Windows NT Workstation version 4.0 
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IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

  Q256986 Description of the Microsoft Windows Registry

SYMPTOMS
========

You may notice the following symptoms:

- World Wide Web Publishing fails to start, and the following event appears in
  the Event log:

  Event ID: 7023
  Source: Service Control Manager
  Description: The World Wide Web Publishing Service terminated with the
  following error: The endpoint cannot be created.

- If you try to stop services such as W3SVC, MSFTPSVC, SMTPSVC, SS LDAP, or SS
  Messaging, the attempt fails with the following error message:

  Error 1721: Not enough resources are available to complete this operation

- Distributed Component Object Model (DCOM) clients that try to connect to the
  DCOM server fail with the following error message:

  RPC_S_SERVER_UNAVAILABLE (0x800706ba) - The RPC server is unavailable

CAUSE
=====

This problem occurs because of improper configuration of the port range settings
in the HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc\Internet registry key or
because the port restrictions for a protocol are configured through the DCOMCNFG
protocol property page.

RESOLUTION
==========

WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.

To resolve this problem, use one of the following methods:

- If you do not want to configure DCOM to use a range of ports, delete the
  registry key, and then restart your computer.

- If you want to configure DCOM on your computer to use a range of ports, use
  the HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc\Internet registry key to
  configure the range of ports, and follow the instructions in the following
  white paper:

  Using Distributed COM with Firewalls
  http://www.microsoft.com/com/wpaper/dcomfw.asp

  If you used the DCOMCNFG utility to configure port restrictions, you may be
  encountering a known DCOMCNFG bug. For additional information, click the
  article number below to view the article in the Microsoft Knowledge Base:

  Q201911 BUG: DCOMCNFG Writes Ports Named Value in Incorrect Format

  Rather than use the DCOMCNFG utility, use Regedt32.exe to configure the port
  restrictions as described in the white paper.

  The number of ports to be opened depends on the number of DCOM applications
  and other services that are running on the computer. For example, each
  instance of a DCOM application process uses one port; Microsoft Internet
  Information Server (IIS) uses a minimum of five ports.

  In addition, it is important to determine the range of ports to be opened. For
  instance, Microsoft SQL Server uses port 1433 for incoming requests and ports
  1024-5000 for outgoing calls. Considering these factors, it is recommended
  that you open a minimum of 15 to 20 ports and use a port range that is above
  5000. For example, configure DCOM to use port range 5000-5020.

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

Configuring the computer to use a range of ports can break other applications on
the system. On systems that are running Microsoft Windows NT 4.0 Service Pack 4
and later, the best alternative is to configure the DCOM application to use the
static endpoint by using the AppId key.

To configure the DCOM application to use a static port by using TCP/IP as the
DCOM protocol, follow these steps:

On the Client Computer:

1. From the Start menu, click Run, type "DCOMCNFG" (without the quotation
  marks), and then click OK.

2. On the Default Protocols tab, move Connection-oriented TCP/IP protocol to the
  top of the list, and restart the computer.

On the Server Computer:

1. From the Start menu, click Run, type "DCOMCNFG" (without the quotation
  marks), and then click OK.

2. On Default Protocols tab, move Connection-oriented TCP/IP protocol to the top
  of the list.

3. Using tools such as OLEVIEW, find your application's AppId globally unique
  identifier (GUID).

4. Start the Registry Editor (Regedt32.exe).

5. Locate the following key in the registry:

  HKEY_CLASSES_ROOT\AppId\{AppId GUID}

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

  Value Name: Endpoints
  Data Type: REG_MULTI_SZ
  Value: ncacn_ip_tcp,0,<port number>

  where <port number> is the static port that you want to use.

7. Quit the Registry Editor.

8. Restart the computer.

Note that your application may not pick up the static endpoint from the registry
if the mapping for the .exe name to the AppId does not exist in the registry.

REFERENCES
==========

For additional information regarding the mapping for the .exe name, click the
article number below to view the article in the Microsoft Knowledge Base:

  Q216051 FIX: DCOMCNFG NT 4.0 SP4 Does Not Write .exe Name under HKCR\APPID

Additional query words:

======================================================================
Keywords          : kbOSWinNT400 kbOSWinNT400sp4 kbDSupport 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : :4.0
Issue type        : kbprb
Solution Type     : kbnofix

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