Unless you have your local IP address assigned to you, there are only three groups of IP's that are valid for you to use on a machine that's connected to the net (that won't collide with other machines). They are:

10.0.0.0 to 10.255.255.255 (Class A)
172.16.0.0 to 172.31.255.255 (Class B)
192.168.0.0 to 192.168.255.255 (Class C)

So make sure your LOCAL network IP's fall within one of these three ranges, or you're more than likely going to have problems.

From --- ANALOGX PROXY SERVER user manual