Implement April 17 2020 addendum
From http://openconnectivity.org/developer/specifications/upnp-resources/upnp/#architectural
The subscription request containing a delivery URL not on the same network segment as the fully
qualified event subscription URL shall not be accepted. For private networks this means that the
delivery URL provided will adhere to the following IP ranges:
10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)