I am facing two problems regarding routing tables.

First problem:
In one of my client machines, I am getting routing table as:
_____________________________________________________
Destination Gateway Genmask Flag M R U Ifac
localnet * 255.255.255.0 U 0 0 0 eth0
default ......
-----------------------------------------------------
In other client machines, I have routing table as:
_____________________________________________________
Destination Gateway Genmask Flag M R U Ifac
10.0.0.0 * 255.255.255.0 U 0 0 0 eth0
default ......
-----------------------------------------------------
How to change Destination from localnet to 10.0.0.0???

I cannot fetch internet to the clinet with Destination:localnet.
Where as other clients can fetch the internet through Gateway (I am use firestarter and have enabled LAN clients to access internet).

Second problem:
One is in my gateway, which has two networking cards.

When I reboot the machine:

both eth0 and eth1 are taken as default

so I have to delete one of them as:
"route del default eth1".
I have to do this all the times, I reboot the machine.
Is there a way to do tell the Debian to take eth0 only as default.
While installing Debian, I chose only eth0 as default network card.

Thanks

What does 'route -n' show on the 'localnet' machine?

On the gateway, are both interfaces being assigned IPs via DHCP? If not, you should be able to fix it in /etc/network/interfaces.

If you use Gnome, try Desktop|Administration|Networking and disable eth1.

I assume KDE has a similar function.