Default route is missing

I upgraded my server from Ubuntu 8.10 to 9.04 and now my default route is missing. So every time I boot I have to manually add it back with the command:

sudo route add default gw 192.168.10.1

How do I make that permanent?

Thanks.


I believe the configuration file is in /etc/network/interfaces on ubuntu to add a gateway a.b.c.d,

The file would read something like:

iface eth0 inet static
address 172.16.0.8
netmask 255.240.0.0
gateway 172.16.0.1

auto lo
iface lo inet loopback