this post was submitted on 20 Sep 2023
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Privacy

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Today we announce that we have completely removed all traces of disks being used by our VPN infrastructure!

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[–] Azzu@lemm.ee 10 points 1 year ago (11 children)

The BitTorrent protocol basically works like this when you download a torrent:

  1. a tracker has a list of clients that have some data of a torrent
  2. you want to download that torrent, so you ask the tracker for this list
  3. after you receive this list, you ask the clients on this list to upload their data to you
  4. 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.

[–] eager_eagle@lemmy.world 2 points 1 year ago (4 children)

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.

[–] Azzu@lemm.ee 1 points 1 year ago (3 children)

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.

[–] dysprosium@lemmy.dbzer0.com 1 points 1 year ago (1 children)

that's so weird, that only one of two people need to have an open port. So the person with the closed port can still establish a connection, both upload AND download. However, this process stops the moment the other person closes his port, then NO connection whatsoever can be established? So we're gonna pretend this makes sense? Or is it about initiating a connection which requires an open port? That'd make a bit more sense

[–] Azzu@lemm.ee 0 points 1 year ago (1 children)

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.

[–] dysprosium@lemmy.dbzer0.com 1 points 1 year ago

I know a bit about NATs, or how I like to call it, LAN, basically. But if you don't even have a NAT to begin with and are directly connected (to your modem), then you don't even need to open a port. Easy peasy

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