You can forward ports so incoming connections on these ports will always be sent to a certain computer. (howtogeek.com)
That's likely the only option you'll see here, but you could also allow incoming connections over a dial - up modem if you have the dial - up hardware. (howtogeek.com)
These include using the system to manipulate behavior, developing the equivalent technique in mice, and making it work in reverse so that it employs incoming connections from other neurons just like it does outgoing connections. (brownmedicinemagazine.org)