I remember that I used this some time ago, and that the official documentation on the UPF website was (and maybe still is) obsolete.
What is vpnc?
Cisco-compatible VPN client vpnc is a VPN client compatible with cisco3000 VPN Concentrator (also known as Cisco’s EasyVPN equipment). vpnc runs entirely in user space and does not require kernel modules except of the tun driver to communicate with the network layer.
So in Debian, I did:
apt-get install vpnc
I created the file /etc/vpnc/upf.conf with the following content:
IPSec ID upf IPSec secret upf IPSec gateway vpn.upf.edu IKE Authmode psk Xauth username u69690 Xauth password chucknorris
Note that I have used some examples for the username and password.
After that, everything worked:
Connect Banner: | Benvinguts al servei de VPN de la Universitat Pompeu Fabra. | Benvinguts al servei de VPN de la Universitat Pompeu Fabra. | VPNC started in background (pid: 5175)...