I want to switch on the fly between several network interfaces: eth0, wlan0, and ppp0. It is easy enough to take down one interface and bring up another. The problem is that the routing table is not set correctly for the new interface. If I specify "GATEWAY=192.168.0.1" in /etc/sysconfig/network then traffic is routed correctly for eth0 (my usual interface). However that is innappropiate for either wlan0 or ppp0, and no packets are routed with this config in place. If I do not specify the gateway, then it is eth0 that fails to route packets correctly. How can I specify the default route on a per-interface basis? Thanks.
