One of my servers just became inaccessible on it's static IP connection, the gateway is missing from that connection, it is now only accessible through the dynamic IP connection. I was just able to fix the problem by adding a route entry.
I was not able to RDP to the machine through it's static IP address, and pings to the machine were also not responding.
RDP to the dynamic address, then add a new default route:
route add 96.0.0.0 MASK 255.0.0.0 96.238.221.146 METRIC 2 IF 0x10006
Now I can get to all the services on the static IP address again....
The key is to make the destination more restricted than 0.0.0.0. Windows doesn't like having multiple 0.0.0.0 routes.
Update: Not sure if this is the long term solution.... A few minutes later, the server was not accessible again from the static IP. Tried deleting the 0.0.0.0 route to the static, tried some other thigns, could not bring the static route up again, so rebooted..... the machine had run fine for weeks, even months, without this problem.