PPSSPP Ad-hoc general info thread

[AdamN]

(10-04-2020 02:26 PM)Zinx777 Wrote:  I also found something called "UDP/TCP hole punching" .
It opens ports under NAT.
There are some open source implementations of it (but it kinda sounds like Relay servers?).

it's not a relay server, it's just a trick to open a random port (which usually for clientside) to be used for serverside too, instead of a dedicated port (which usually used by server/host)

The logic is (using PPSSPP as the app example):
1). PPSSPP1 & PPSSPP2 connect to a STUN server on the internet and maintain that connection so the port won't be closed down by the router, when connected to a STUN server it will know which public IP & port it's using (random port)
2). Player1 that use PPSSPP1 tells Player2 that use PPSSPP2 (eachother) which IP:port (the one used to connect to STUN server) they are using through messaging app (discord, whatsapp, etc)
3). After getting eachother IP:port PPSSPP1 & PPSSPP2 can start communicating.
*No.2 can be made automatic if we have a customized server on the internet to exchange information of each players IP:port (can be located at the same place with STUN server, or customize the STUN server to do this)
** Since PSP games requires dedicated ports, the random ports need to be mapped (similar to how tunneling works)
***hole-punching doesn't guaranteed to work 100% as it's a trick (depends on the security level of the ISP)