I have a Moto NVG510. I would like to open up 1 port on an internal box to a specific external host. In other words: I have a host at work, and I would like that host to be able to connect to my PC at home at a specific port. I don't want to open up this port to the entire 'net; just this specific host.
How do I do that? When I try "advanced port forwarding", it requires a specific _source_ port too; which is ridiculous, because most often source ports are pretty random. Any suggestions?