not too sure about ubuntu, but I guess the ppp impementation is pretty standard. In your ppp config file (on my debian system its in /etc/ppp/options), just plug in or uncomment the 'defaultroute' line. The route will be added and removed automagically as the link goes up and down.
For more info... 'man pppd'.
Last edited by angrybeaver; 04-08-2005 at 12:46 AM.