COM: Administration


 


COM Header


 


COM\DCOM Administration


 


Description: The Component Object Model (aka COM) is a platform-independent, object-oriented system to create software components that can interact.  A COM application usually consists of an executable file and additional components such as DLL files that are used to perform various functions.  The key feature of COM is that it is language-independent and promotes the reuse of components from different vendors.  DCOM (Distributed COM) is an extension of COM that allows component interaction across machine boundaries – across the LAN, WAN or even over the Internet.


A component is nothing more than a piece of code that exists as an executable file or DLL.  A COM component can act in either a client (requesting service or functionality from another component) or server (providing service or functionality to other components) role. 


 


 


Scoping the Issue:


 


DCOM specific questions



  • Are the end-users affected and Local/Domain Administrator accounts affected or just the end-user accounts?

  • Are there any network related errors? Is RPC (DCOM) working?

General DCOM related questions



  • When did the issue start occurring?

  • What has changed?

  • Application update?

  • Hardware update/failure?

  • Driver update?

  • Antivirus definition update?

  • Security hotfix update?

  • GPO modification?

  • How did you get notified about the problem? Did the end-users call the helpdesk?

  • Are all the client workstations and servers affected?

  • What OS and Service Pack are affected?

Windows NT 4.0 Wks/Srv/TS


Windows 2000 Pro/Srv


Windows XP Pro


Windows Server 2003


Windows 2008



  • Does the issue occur on machines in the same subnet or just on a LAN or WAN?

  • Can you ping the server when the issue occurs?

  • Can you open network shares when the issue occurs?

  • How frequently does the DCOM error occur?

  • Does the DCOM errors occur during any particular time of day, or does it occur when a certain application is run?

  • Are there any application specific errors on the screen?

  • How does the machine recover? Do you just wait? Or do you have to reboot the machine?

 


 


 


Data Gathering: When troubleshooting COM\DCOM related errors, keep in mind that the issues could be related to their permission lockdown, network infrastructure, 3rd party or custom application.


 



  • Collect MPSReports/MSDT

  • Collect Process Monitor – Process Monitor should be gathered on both the Server and as well as the clients that are having the issues.

  • Collect Network trace

  • Get a list of DCOM permissions

  • Export The HKEY_CLASSES_ROOT Key From The Problem Machine

 


 


 


Troubleshooting / Resolution:


 


Make sure that DCOM is enabled on the local and remote machine that you are troubleshooting.


 


Windows 2000 DCOM Settings


 


To Enable DCOM Using the DCOM Configuration Utility (Windows 2000)



  1. Click Start, and then click Run.

  2. In Open, type DCOMCNFG, and then click OK

  3. Click the Default Properties tab.

  4. Next to Enable Distributed COM on this Computer, please make sure that the check box is checked.

  5. If you want to set more properties for the computer, click Apply to enable DCOM. Otherwise, click OK to apply the changes and quit Dcomcnfg.exe.

  6. Restart the operating system for the changes to take effect.

 


Windows XP/2003 DCOM Settings


 


Windows XP or Windows Server 2003


To Enable DCOM Using the DCOM Configuration Utility (Windows 2003 and XP)



  1. Click Start, and then click Run.

  2. In Open, type DCOMCNFG, and then click OK

  3. Click the Component Services node under Console Root.

  4. Open the Computers folder.

  5. For the local computer, right-click “My Computer”, and then click Properties.

  6. For a remote computer, right-click Computers folder, point to New, and then click Computer.

  7. Type the computer name.

  8. Right-click the computer name, and then click Properties.

  9. Click the Default Properties tab.

  10. Next to Enable Distributed COM on this Computer, please make sure that the check box is checked.

  11. If you want to set more properties for the computer, click Apply to enable DCOM. Otherwise, click OK to apply the changes and quit Dcomcnfg.exe.

  12. Restart the operating system for the changes to take effect.