I tried using DHCP (forcing DHCP with the above istruction), in that case the IP address of my PC is 192.168.99.38 and the IP address of N+ is 192.168.99.36, netmask 255.255.255.0, and with a fixed IP; I tried with different netmasks 192.168.2.0, 10.10.10.0.
When I have seen the ping error message, I also had the same idea, a netmask mismatch, but now I think that my N+ has a problem.
Could be and interrupt management issue? The ethernet board seems to works fine but the IP stack doesn't receive anything.
Marco
What is the N+ Default Gateway IP address?
Try this:
Debug.Print(Microsoft.SPOT.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()[0].GatewayAddress);
Is the N+ Gateway Address the same as the IP address of your router? Or is it different? It should be the same.
Also, try running a traceroute for the N+ IP address and see where it's failing.