/31 aka 255.255.255.254 netmask with Windows
Windows GUI prevents you from setting this with helpful error message of "All of the bits in the host address portion of the IP address are set to 0". IP stack seems to be fine with /31 networks so just set it from CLI. netsh interface show interface netsh interface ip set address name="Local Area Connection" source=static addr=10.71.219.238 mask=255.255.255.254 gateway=10.71l.219.239