EDIT: We connected an air card to the computer to use a different Internet connection and using the Cisco software, we were able to successfully connect to our VPN server. I just don't understand why the ShrewSoft VPN client would connect but the Cisco connection won't.
I'm not our network admin so sorry if I butcher some of the terminology.
I have a computer at remote site that connects to our network through Cisco VPN. It uses the Cisco VPN software to do so. The problem is that the computer at this site cannot connect to our VPN because it is getting error "Reason 412: The remote peer is no longer responding."
Cisco Reason 412 http://dl.dropbox.com/u/35257/cisco-error.png
To see if perhaps something on their network was blocking the connection, I installed the ShrewSoft VPN client on the computer, imported our .pcf file and connected with no problem. I have tried two different versions of the Cisco VPN software (4.8.0.* and 5.0.03.*) and have the same problem.
I installed Wireshark on the computer and have confirmed (while trying to connect through Cisco) that the computer is trying to contact the VPN server but is not receiving a response.
Wireshark packets http://dl.dropbox.com/u/35257/wireshark-vpn.png
We are not having any other problems regarding users not being able to connect. I'm at a loss at what else to check. I'll be monitoring this and have access to the computer at any time.
Have you tried going into your connection profile and changing the transport to IPSec over TCP instead of IPSec over UDP? that fixes a lot of weird issues like that for me.