Change default gateway ubuntu

Here's the complete answer, in case it helps others:

To make packets with destinations 192.168.10.* use eth0, and all other packets use eth1:

1) View your current routing table

One entry will be something like "default via 192.168.1.1" where 192.168.1.1 is your router (a.k.a.

gateway) ip address. Remember the gateways for eth0 and eth1, as we'll need them later.

2) Delete the default route(s).

(Warning: this will kick you offline.)

3) Add a new default route (this will bring you back online). Replace 192.168.1.1, below, with your gateway ip address from above.

4) Add a specific route that will be served by eth0.

More-specific routes automatically take precedence over less-specific ones.

Finally, you can ask Linux which interface will be used to send a packet to a specific ip address:

If the configuration worked, packets to 8.8.8.8 (Google's server) will use eth1.

Packets to any ip on your local network:

will use eth0.