Fix for Cisco VPN Error 51

I don't use Apple Macs but I do use Cisco VPN client software. However, it appears to me that Cisco VPN

and Macs sometimes have problems with each other (that much was pointed out by blogger Rob Slifka back in February). Today I come across a post by Rob Griffith on sister publication Macworld who has found a fix for a recurring Error 51 problem.

Griffith writes:

While the Cisco VPN Client works well most of the time, sometimes when I try to launch the application, I’m greeted with this error message in place of the usual connection dialog:

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 error is clearly incorrect, because my machine’s networking capabilities are otherwise fine ...

He points readers to a fix that involves a simple command line administrators can execute in Mac's Terminal.

Do your Mac users come across other Cisco VPN client problems? 

See also:

Cisco user has a Seinfeld flashback with a Cisco VPN client error message

Fixes for Apple Leopard breaking Cisco VPN client

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