#401 Add support for subnets larger than /8 as seen in RFC3330

[Four Eighteen]

Subnets larger than /8 are not supported.

There are such valid subnet masks, as can be seen in the RFC documentation referencing reserved subnets such as the Multicast subnet.

https://tools.ietf.org/html/rfc3330#section-3

   224.0.0.0/4          Multicast                              [RFC3171]
   240.0.0.0/4          Reserved for Future Use        [RFC1700, page 4]