Cisco Unified Communications Manager (CallManager)

DCOM Unable to Communicate with Cisco CallManager

Document ID: 71318

Updated: Aug 01, 2007



Distributed Component Object Model (DCOM) is the support module for Dynamic Link Library (DLL)-based COM objects. DCOM is a software architecture model that is an intrinsic part of Windows, of most Microsoft products, and of many non-Microsoft products that take advantage of COM+ or DCOM.



There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

  • Media Convergence Server (MCS) 7835 (other MCS platforms applicable)

  • Cisco CallManager 3.x and Cisco CallManager 4.x (other applicable versions of Cisco CallManager)

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.


Refer to Cisco Technical Tips Conventions for more information on document conventions.

DCOM Support on Windows

The default protocol for the DCOM protocol on Windows 2000 on which Cisco CallManager runs is the connection-oriented Transmission Control Protocol/Internet Protocol (TCP/IP) protocol. DCOM on Windows 2000 does not support any of the datagram protocols.


In Cisco CallManager, the system log in the Event Viewer displays many errors that state:

DCOM was unable to communicate with the computer
callmanager using any of the configured protocols.

This can be due to the Component Services Administrative tool or because DCOMCNFG incorrectly allows you to add Datagram User Datagram Protocol/Internet Protocol (UDP/IP) and Datagram Internet packet exchange (IPX) protocols to the Default Protocols tab. Windows 2000 does not support any datagram protocols.


In order to resolve this issue, make sure that the connection-oriented protocols (TCP/IP) are in the DCOM Protocols tab. Remove any of the datagram protocols (UDP/IP or IPX) from the DCOM Protocols tab.

  1. Choose Start > Programs > Administrative Tools and click Component Services in order to launch the Component Services Administrative tool.

  2. In the console tree of the Component Services Administrative tool, right-click the computer on which you want to configure the protocol in order to bring up the Context menu.

  3. Click Properties in order to bring up the Computer Properties dialog box.

  4. Go to the Default Protocols tab.


  5. If you have any of the datagram protocols (UDP/IP or IPX) listed here, click to select, and then click Remove.

    If you do not have any of the connection-oriented protocols in the list, click Add in order to bring up the Select DCOM Protocol and Endpoint dialog box.

  6. Choose Connection-oriented TCP/IP Protocol as the protocol sequence, and then click OK.

  7. Add any or all of the connection-oriented protocols to the default protocols.

  8. Click Move Up in order to move Connection-oriented TCP/IP Protocol to the top of the list.

  9. Restart the computer or Cisco CallManager server for the changes to take effect.

  10. Delete all the DCOM errors under the System Log in the Event Viewer and verify whether the same occurs again.

DCOM Errors on the Event Viewer

The Event Viewer displays many DCOM errors on the Cisco CallManager server.

Complete these steps in order to resolve this DCOM errors issue:

  1. Reboot the CallManager (both the Publisher and Subscriber) servers. Then check to see if the DCOM errors have disappeared.

  2. Make sure that the host and lmhost files located at C:/WINNT/system32/drivers/etc/ on the Publisher and Subscriber are updated. These files contain the mappings of IP addresses to computer names (NETBIOS name). Edit the host and lmhosts file using any text editor (if required).

  3. Run DBLHelper.exe located at C:/Program Files/cisco/bin only on the Publisher server. Republish and reinitialize the database using the DBLHelper utility. For more details about DBLhelper, refer to Using DBLHelper to Reestablish a Broken Cisco CallManager Cluster SQL Subscription.

Permission Error in the Event Viewer

The Event Viewer shows an error that states: The application-specific permission settings do not grant Local Activation permission for the COM Server application to the user NT AUTHORITY\NETWORK SERVICE. The error message is as shown here:

Event Type:	Error
Event Source:	DCOM
Event Category:	None
Event ID:	10016
Date:		09/12/2007
Time:		10:58:05 AM
Computer:	CMUNITY
The application-specific permission settings do not grant Local Activation permission for
the COM Server application with CLSID {0C0A3666-30C9-11D0-8F20-00805F2CD064} to the user
NT AUTHORITY\NETWORK SERVICE SID (S-1-5-20).  This security permission can be modified
using the Component Services administrative tool. For more information, see Help and
Support Center

    Complete these steps in order to resolve this error message related to DCOM:

  1. Go to Start > Programs > Administrative Tools > Components Services.

  2. Expand Component Services > Computers > My Computer > COM+ Applications.


  3. Click View > Detail. Look for the entry with the Application ID as shown in the error message. In this case, 0C0A3666-30C9-11D0-8F20-00805F2CD064.

  4. Right-click on the application and go to Properties. Go to the Security tab and grant the NT AUTHORITY\NETWORK SERVICE account Activation permissions.

  5. Reboot the Cisco Unity server after you have performed these steps.

Related Information

Updated: Aug 01, 2007
Document ID: 71318