Windows 10 PC communicating on two networks

I have a laptop with with a single NIC and an IP Address of 10.7.1.182. I can talk to another system, 10.7.1.199, no problem. Of course, same network. But I cannot talk to a system with an address of 10.16.1.200. Naturally, not on the same network. Snooping the LAN the laptop is not even trying to find 10.16.1.200! No ARPs, no nothing. I am pretty sure a route is needed to get him to try and talk to 10.16.1.200. Can't use static IP Addresses unfortunately.

Will setting a route into the laptop route table solve this and if so what would it look like?

Solution 1:

Depending on the size of the network mask, your laptop makes a routing decision for any outgoing packet. Assuming a /24 network, any address 10.7.1.0 to 10.7.1.255 is considered local - ARPed and sent to directly. Anything else is considered non-local and sent to the default gateway, or a better one, depending on the local routing table. Without any matching route, the packet is dropped.

So, either your default gateway has a route to 10.16.1.200 - then everything should be working - or you need to set up a route using a different gateway.

If 10.16.1.200 is located on the same L2 segment you could make your laptop send to it directly (route add 10.16.1.0 mask 255.255.255.0 0.0.0.0), or decrease the mask length to at least /19 (or 255.192.0.0) to encompass the destination. Of course, you'll need to do the same on the destination to find the way back.

Alternatively, you could add an IP address from 10.16.1.0/24 to your NIC.