This is more of a note for myself, and for the net as the error that I keep running into is not documented all that well online. Well, at least, when I search for Error 51: Unable to communicate with the VPN subsystem most of the links that I come across say just restart the VPN subsystem and life returns. This does not fix the problem I get with this error, which comes usually after a OS update.
The fix for me is to completely uninstall the Cisco VPN application, which is actually a command-line activity. All you have to do is run /usr/local/bin/vpn_uninstall as root (sudo). This does the full uninstall, and then you can re-install the application and life should return. If you just update the software in place, the error does not go away.
So there, at least I know I can find out what to do next time I have to jump through this hoop.
-c
I had the same, after a Snow Leopard install. The fix was to just use the new VPN functionality included in Snow Leopard that is compatible with Cisco head ends. Worked like a charm.
Thanks for this. I found this same solution on Cisco’s site, this also works for Leopard as well. One note though: check to see if the client machine has VPN contents at /usr/local/, if not reinstall, uninstall and install again.
If you get this after switching your Mac to 64 bit booting in Snow Leopard, the best solution I’ve found is to use the built-in VPN client. The data in your pcf file has all the info the client needs.
The only tricky part for me was decoding the shared secret. The trick there is to search the web for a publicly available shared secret decoder.
Amen to the built-in VPN client. I switched to that once I upgraded to Snow Leopard, and it has been working like a charm ever since.
Here’s what I used to fix this problem:
http://forum.maas360.com/go/mobileitexpertise/fix-for-cisco-vpn-error-51-unable-to-communicate-with-the-vpn-subsystem/