How To change the default gateway

Fire following commands at your console.

/sbin/route shows the IP routing table.
/sbin/route del default deletes current default gateway.
/sbin/route add default gw xxx.xxx.x.xxx adds a new default gateway.
[ xxx.xxx.x.xxx is ofcourse the gateway you want to set as default ]

After changing default you need not to restart network.
But if you want , you can restart your network by

/etc/init.d/network stop
/etc/init.d/network start

Proxy settings can be changed by changing /home/web/.wgetrc file.