The BitTorrent protocol basically works like this when you download a torrent:
a tracker has a list of clients that have some data of a torrent
you want to download that torrent, so you ask the tracker for this list
after you receive this list, you ask the clients on this list to upload their data to you
repeat 3. until you have the whole torrent
As soon as you have something downloaded, you become a client on the list of the tracker that theoretically has the torrent available for others. So you would become the “client being asked” of step 3 as well.
But how can you be asked? In a P2P networking context, you can only “be asked” if you have a port open that allows connections to it. Otherwise it’s as if you gave people your home adress but your mailbox has a hole on the bottom that leads directly to the garbage can beneath it, so all mail is immediately lost. Completely unusable.
In other words, it’s (basically) impossible for you to send the torrent data to someone else. You’re a leecher, someone that doesn’t give back to others. If everyone would act like you, torrents wouldn’t work at all.
That’s why I said (basically). If another user has a port open and you connect to them through their open port, a bidirectional connection gets established and then you can also upload. But if the other user also didn’t have a port open, then BitTorrent wouldn’t work. You rely on other people to have ports open, if everyone was using mullvad, then it would stop working.
In other words, it’s (basically) impossible for you to send the torrent data to someone else.
I don’t know how (in)accurate this description is, but I’ve been seeding hundreds of GB since Mullvad dropped port fwd. Same for the old times when I didn’t bother using a VPN, I never had to enable port forward in my router for it to work.
That’s why I said (basically). If another user has a port open and you connect to them through their open port, a bidirectional connection gets established and then you can also upload. But if the other user also didn’t have a port open, then BitTorrent wouldn’t work. You rely on other people to have ports open, if everyone was using mullvad, then it would stop working.
You could read a bit about NAT, which your router does, if you want to know more. But yes, of course only the initiation requires an open port, otherwise like you said, it doesn’t make sense. As soon as a connection is established your router knows where packets should be sent and an “open” port is not necessary.
Removed by mod
The BitTorrent protocol basically works like this when you download a torrent:
As soon as you have something downloaded, you become a client on the list of the tracker that theoretically has the torrent available for others. So you would become the “client being asked” of step 3 as well.
But how can you be asked? In a P2P networking context, you can only “be asked” if you have a port open that allows connections to it. Otherwise it’s as if you gave people your home adress but your mailbox has a hole on the bottom that leads directly to the garbage can beneath it, so all mail is immediately lost. Completely unusable.
In other words, it’s (basically) impossible for you to send the torrent data to someone else. You’re a leecher, someone that doesn’t give back to others. If everyone would act like you, torrents wouldn’t work at all.
Removed by mod
I’ve been downloading and seeding ever since too. People are dismissing / moving away from mullvad for nothing.
That’s why I said (basically). If another user has a port open and you connect to them through their open port, a bidirectional connection gets established and then you can also upload. But if the other user also didn’t have a port open, then BitTorrent wouldn’t work. You rely on other people to have ports open, if everyone was using mullvad, then it would stop working.
Removed by mod
I don’t know how (in)accurate this description is, but I’ve been seeding hundreds of GB since Mullvad dropped port fwd. Same for the old times when I didn’t bother using a VPN, I never had to enable port forward in my router for it to work.
Removed by mod
You could read a bit about NAT, which your router does, if you want to know more. But yes, of course only the initiation requires an open port, otherwise like you said, it doesn’t make sense. As soon as a connection is established your router knows where packets should be sent and an “open” port is not necessary.
Removed by mod
Isn’t this what STUN is for?
It’s not that simple. Who hosts that server? Which torrent clients implemented support for it? What about symmetric NATs?
In short: no. In long: read up on it yourself.
It’s not needed to leech but it’s pretty important if you want to seed more anonymously