Recently, I ran into a very frustrating problem. I have a Fedora Core 14 machine which had been running without issues for a long time. I have been updating it regularly. One day, I decided to restart it for some reason. It came back fine but lost Internet access. The LAN networking was just fine.It actually took me a while to figure out that the Internet connectivity was broken.
After some research, I concluded that the default gateway configuration had been lost. Apparently, one of the updates changed the networking behavior. Earlier, it used to obtain the default gateway automatically, but it wasn’t doing that now.
I tried setting the default gateway by editing files, etc. but it would get overwritten. Finally, the command that did it for me was the following:
route add default gw <router_IP_address>