Your best bet will be to call whoever is responsible for configuring the router. See, there's nothing magical about IP addresses that make it a router, *any* machine could be a router. If the machine you are running the script on is connected to the same network as the router you are interested in is, its routing table might list it. But maybe it doesn't. Maybe you can run a router discovery protocol. But maybe you can't. It all depends on the network policies. So contact the person or people responsible for setting up the router and/or network. They should know. We don't. All we can say is that 0 < x <= 255.
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