Using Cisco VPN @ Ubuntu

$ sudo apt-get install vpnc

$ vi YOUR_VPN_CONFIG_FILE (example: vpn_A.conf)
# comon VPN using IPSec + IKE auth
IPSec ID YOUR_VPN
IPSec gateway VPN_GATEWAY_NAME_OR_ADDRESS
IPSec secret IPSEC_SHARED_SECRET
#
Xauth username VPN_USERNAME
Xauth password VPN_PASSWORD
IKE Authmode psk
#
Target networks 10.0.0.0/8 (change it accordly, just an example)
$

tip: you can use "pcf2vpnc" to convert the cisco client config file for windows;
if after install it claims on a missing library, you'll need this:
$ wget http://www.unix-ag.uni-kl.de/~massar/soft/cisco-decrypt.c


To establish the VPN tunnel:

$ sudo vpnc PATH_TO_CONFIG_FILE

To disconnect:

$ sudo vpnc-disconnect