I really, really like Macross, but isn't the original Gundam a bit more influential? If we include Super Robot stuff, some early Go Nagai series are probably way up there for influence too. Rocket Punches, etc.
A TCP packet has a segment for a numerical descriptor which is metaphorically referred to as a port. A lot of networking hardware and software filters based on that packet segment, or directs it to particular software registered as 'listening' for that number.