Comment by 5e92cb50239222b
3 years ago
You need to be able to accept incoming connections to be able to fully participate in the network. Last time I seriously looked into this, BitTorrent clients didn't support any sort of NAT hole punching (and they often work over TCP in any case). Try running a client with and without a forwarded port and you will see massive difference in the number of peer connections.
Transmission has supported UPnP and NAT-PMP for many years. Although it doesn't always work as reliably as having a client with directly routable address(es), it does exist and works okay.
I think I might be doing that already, as this is the first I've heard of this. Unless Mullvad was automatically opening a port for me.
Is it possible a lot of average torrenters are already not port forwarding?
> NAT hole punching
Could we just throw a STUN service in front of this, then?
So you're saying there's a chance
Of course, but if everyone is behind the NAT then no one in the swarm can connect to any one. If this is a popular torrent when someone with the connectivity would show up, eventually, but otherwise good luck. Recently it took me four months to complete one torrent and I was the one with the real IP.