vpnc (http://www.vpnc.org/)is an alternative for cisco vpn client, because it's totally competable with cisco 3000 vpn concentrator (IPSec).
You can install vpnc using yum in fedora Linux.
Make your /etc/vpnc.conf like this:
IPSec gateway vpn.ox.ac.uk
IPSec ID 'groupname'
IPSec secret 'grouppassword'
Xauth username 'username'
If you only know the decoded group password from your institution distributed cisco client file, like me, you can decode the password at http://www.unix-ag.uni-kl.de/~massar/bin/cisco-decode, and put the decoded clear text password in your vpnc.conf, which won't accept the encoded password.