- install vpnc, cd /etc/vpnc, create the config file: dp-auth.conf with the following content:

IPSec gateway FIREWALLIP

IPSec ID GROUPNAME

IPSec secret GROUPPASSWD

Xauth username YOUR-DP-AUTH-USERNAME

then run command "vpnc dp-auth" to connect your VPN, "vpnc-disconnect" to disconnet your VPN after your work.