BitTorrent

A few tips, in the hopes that it’ll help someone else. (Aside: don’t download illegal stuff with BitTorrent. Do download the many awesome, legal things on BitTorrent, such as Ubuntu torrents.)

  • You can encrypt your BitTorrent traffic, which is meant at circumventing ISPs that feel like being pains and blocking traffic. However, “Enabled” isn’t the value you want. You want “Forced.” In uTorrent, this is under Preferences -> BitTorrent.
  • If you don’t upload at all, other nodes will “choke” you by refusing to talk to you. It doesn’t seem to me like it has to be entirely equitable; I’ve capped my upload at a pretty small number, but am downloading around 100 kB/second (800 kbps).
  • You’ll have a port number for incoming connections. If this port isn’t coming through (such as if you have a “default-deny” policy), things will work, but they’ll be unbearably slow. As an aside, if you’re behind an OpenBSD firewall (using pf), have a local IP of 192.168.1.79, and use the randomly-selected port 26689 as your local port for BitTorrent, the firewall rule looks like rdr on $ext_if proto tcp from any to any port 26689 -> 192.168.1.79 port 26689. Remember to flush the rules (pfctl -F rules) and then (possibly required? possibly done automatically with the flush?) load them back in (pfctl -f /etc/pf.conf).

With these three principals in mind, my (legitimate) download went from 0.8 kB/sec to 145 kB/sec.

Huh, a neat tip… If you pick a torrent from one site, but it’s something identical to what other sites have, add the additional trackers in to the first download, which will give you more peers!

Oh, another tip: don’t arbitrarily set a download limit! My downloads wouldn’t break 145 kB/sec or so, until I realized that I’d set a limit of 150 kB/sec. I removed the limit and am suddenly at 400 kB/sec. (Incidentally, our available bandwidth has suddenly plunged to nothing…)

One final note: Peer Guardian is good, but don’t run it unnecessarily, since it blocks a lot of legitimate traffic. Including, oddly, Steam’s servers (for games like Counter-Strike and TF2), apparently because they use Limelight’s CDN, and they’ve dubbed Limelight bad?

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