"The terminology used is somewhat confusing… I’m not really sure what is meant by a “cone.”" I think the linked-to Wikipedia page makes it pretty clear, it's s

"The terminology used is somewhat confusing… I’m not really sure what is meant by a “cone.”" I think the linked-to Wikipedia page makes it pretty clear, it's simply a reference to the conical (funnel-like) shape of the right-hand side of the illustration (http://en.wikipedia.org/wiki/Full_cone_NAT#Methods_of_port_translation http://en.wikipedia.org/wiki/Full_cone_NAT#Methods_of_port_t...). Full-cone NAT allows inbound connections from any external host, i.e. it's an unrestricted funnel (or cone).