Linux 6.2 Route won’t stay put

I can ping the inside Eth0 on the cisco 2610. Cannot ping outside IP. One route add eth0 default gw 192.168.0.x -later I can ping outside but only for a few seconds then it’s back to the connect: network unreachable.
RedHat 6.2 (Zoot) HP Netserver. I’m Crash Coursing this new IT position. hehe but who doesn’t at some time?

Thnx