My default gateway is (FIOS). I am running some Windows 2012R2 servers under Hyper-V. When I set up the servers, I *believe* the Hyper-V Manager also added a network configuration for the VMs. The VM IP addresses are 172.18.x.x and the subnet mask is

BUT the subnet mask on the Host (WIndows 10 Pro) for this network connection is

My question is: why?