VMware Fusion and Cisco VPN on Mac OS X – Fixing a Hiccup

I’m using a Cisco VPN Client (4.9.01) on Mac OS X Leopard (10.5.4). Yesterday I installed VMware Fusion (1.1.3), and today I noticed that my VPN wasn’t working anymore.

The error:

"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."


After some rooting around I suspected that Cisco was getting hung up on vmnet1 and vmnet8, VMware’s virtual network interfaces. My troubleshooting process pretty quickly landed on restarting the Cisco kernel extension, which fixed it. There are multiple ways to do this, but here’s the commands I used:

sudo /System/Library/StartupItems/CiscoVPN/CiscoVPN stop
sudo /System/Library/StartupItems/CiscoVPN/CiscoVPN start

That cleared up the problem.

Update: Also check out this article at Mac OS X Hints - A fix for ‘Error 51′ with the Cisco VPN Client.

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