TCP vs UDP for Peer-to-Peer communication in the protocol

[Aradhya2708]

UDP is objectively easier to implement but could it be more susceptible/prone to NAT blocking?

TCP is used in most known P2P sharing applications (ipfs for e.g.,), and is reliable for files and content of our application, but Windows OS does not allow binding two processes to the same port (SO_REUSEPORT system option), or does it?

[Asharma538]

TCP is the default choice when you want to transfer messages reliably.

Recent versions of Windows (since XP) don’t allow two processes to bind and listen to the same port.

However, it does allow one process to bind to 0.0.0.0:PORT and another to 127.0.0.1:PORT, since they’re on different interfaces, but still only one will receive the request.

On Linux, you can use the SO_REUSEPORT socket option to allow multiple processes to bind and listen to the same port.

In my opinion, you can keep a master process and transfer information via IPC.

[Aradhya2708]

Even if we implement a good IPC, I can ultimately not listen and send through the same PORT. So for the NAT/Wifi-Router it'd still be two different applications. I cannot naively establish a P2P connection between two symmetric peers, both behind a NAT wall. I'll checkout if we can use different interfaces tho