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I know that pfsense is a very effective tool for restricting bit torrent traffic. I was wondering how it actually manages to do that ? There's not much information available on this. The more technical, the better.

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This is more a comment than an answer to your question but there might be some serious security concerns with pfsense when it comes to the usage of cryptography. I encourage you to look at this eprint.iacr.org/2012/588.pdf –  user15502 Oct 29 '12 at 22:30
    
@Alexandre I wasn't aware of this issue with pfsense. Appreciate the input but still no answer. –  Kasisnu Oct 29 '12 at 23:01
    
Kasisnu - that is because it isn't a good tool for this. Check out @Rook's answer! –  Rory Alsop Oct 29 '12 at 23:02

1 Answer 1

As far as I know pfsense performs very simplistic traffic shaping where by it prioritizes traffic based on port range. This is just so that you can play games with someone else using BitTorrent on the network. This is just to be friendly, this is not for "security".

Trying to filter all BitTorrent traffic at the gateway is very a difficult problem and a VPN or another type of tunnel can always be used to undermine this kind of filter.

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+1 Exactly - it isn't a 'very effective tool' - it is just a port restriction tool. –  Rory Alsop Oct 29 '12 at 18:55
    
Thanks @rook. Between the Wikipedia article on pfsense and the fact that they use it at my library to block torrent traffic, I'd assumed it was effective. I guess it could be blocking out the trackers which would in turn restrict all torrent traffic. Its just a guess and I probably might be wrong about this but not knowing how its working is killing me. –  Kasisnu Oct 29 '12 at 22:53
    
@Kasisnu Blocking trackers will not restrict torrent traffic, in fact most torrents, and almost all torrents on ThePirateBay use magnet links backed by a DHT compromised of millions of ip addresses. pfsense is just blocking or rate limiting a port range, that is dead simple, and trivial bypass. Trying to block BitTorrent is extremely complex and it sounds like you are doing it wrong. Maybe you should try using BitTorrent sometime, its a pretty awesome technology. –  Rook Oct 30 '12 at 2:55
    
I know its awesome technology and I use it all the time. But since it wasn't working on this particular network, it got me curious. Thanks. I'll try and find what I might be doing wrong. –  Kasisnu Oct 30 '12 at 6:59
    
Note: I've always thought it to be impossible(especially when using encrypted torrents), but I have a friend who apparently cracked the code to doing 100% blocking of bittorrent at the gateway, assuming VPNs and such aren't involved. No idea how he did it, but last I heard he was trying to sell it to some big networking names –  Earlz Apr 28 '13 at 3:21

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