Question

I want to provide a direct connection between two instances of my program, which are located on two different computers.
I already have the means to obtain the IP addresses, but how do I make a connection between my programs and have no trouble with the firewall or ports?
I need to send serialized objects through the connection.

Edit2: The specific term is peer-to-peer connection.

Edit: I see I need to explain the “no trouble” part.

First, when a program attempts to communicate to the internet, the annoying Windows Firewall permission dialog opens.
On Windows 7, you have two checkboxes:
1. Allow on private (home/work) networks, which is checked by default and, sometimes, cannot be unchecked.
2. Allow on public networks, which is either checked or unchecked by default…

NO ONE I know makes sure that all the check boxes are checked. NO ONE.
This can interrupt the program sometimes in bad ways, without people knowing!

Next… Most people are behind a router and routers usually block all the requests to undefined ports, unless the rules are changed.
Nobody will accept to add these rules just to use a program. Nobody.

Answer 1

So, using a TcpClient and a TcpListener works… as long as I forward the ports on the listener’s router.
So this is not an option.

I ended up using my database to queue commands and check for them every once in a while, and dequeue them when necessary.

For the moment, I cannot find any good answer.