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Error 51

Summary Cisco VPN Client displays error message "Error 51: IPC socket allocation failed with error %xxxx." when attempting a connection.
"Error 51: Unable to communicate with the VPN subsystem. Please make sure that you have at least one network interface that is currently active and has an IP address and start this application again."

The Cisco Systems VPN demon is not started:

  • Windows (7/ Vista/ XP/ 2000): Select Start > Control Panel > Administrative Tools * > Services. Right-click on the Cisco Systems, Inc. VPN Service service and select Properties.

    Ensure the Startup type is set to Automatic and the Service Statues is Started. If not click the Start button. Click OK to save the settings. The Cisco Systems VPN Client should now start.
* If this icon is not visible, select Classic View from the left hand pane.
  • Mac OS X: Following an update to Mac OS X 10.5.7 (or higher) this Error 51 is displayed. Open a terminal window and run the following command:

    sudo SystemStarter restart CiscoVPN