Why it is technologically impossible to block modern filesharing.

Yet again, our country’s government has demonstrated a complete inability to grasp the fundmental issues involved in a technology-related issue. I’m talking about the recent news story that the British government plans to introduce legal sanctions against ISPs who do not take “concrete steps to curb illegal downloads” (BBC News, 22 Feb 08). In order to avoid these sanctions, what could the ISPs do? Here is a list of a few suggestions, and reasons why they are completely ineffective:

  • Packet sniffing – This has two major failings:
    1. Any kind of packet-sniffing on the amount of data ISPs are constantly shuffling around is going to require some hefty (and expensive) equipment
    2. It is will be instantly circumvented by the introduction of encryption by the filesharing protocols (in fact, according to Wikipedia, bittorrent already uses this to circumvent some ISPs throttling).
  • Block filesharing ports – This is a non-starter as most filesharing applications seem to use a range of ports. If the ISPs start down this route, the filesharers will simply move to different ports (port 80, anyone?). Sooner or later they will block some of the higher-numbered ports which people and businesses care about – blocking port numbers over 2000, for example, would mean that I could not access my VPS’ admin console, my place of work could not update their website and I could not access my svn repository preventing me from performing my job.
  • Block access to websites which facilitate filesharing – This is the simplest (and perhaps least effective!) method of trying to control filesharing. This month, the Danish authorities ordered one ISP to block access to a website called “The Pirate Bay”. According to one source this action resulted in a raise in traffic to the site, from Denmark, of 12%. Clearly censoring the web in this way is not going to work (as well as being questionably legal, anyone remember free-speech?).

Even if the ISPs do find an effective means to block the current popular filesharing software the users will just start using something else, potentially a brand-new protocol and this whole saga will start again. And what of the people who use filesharing technology to distribute legitimate files. I have used “bittorrent” software to download DVD images of some Linux distributions, perfectly leagally (they are free to distribute and re-distribute), as the distributions in question do not, and cannot, provide any other means to downloading the large images (usually in excess of 4GB). How will the ISPs be able to block illegal sharing and still protect the interests of organisations which legitimately provide software for free?

Clearly the coorporations, which are pushing the government for this action, would be better off looking at themselves and trying to understand why people seem to prefer piracy to legitimate routes of acquiring products. One BBC article (whose link I have misplaced, sorry) sums it up quite neatly, saying that the quality of pirated downloads is superior to that of purchased downloads (aside: the poor quality of downloaded music is why I still buy CDs and refuse to buy from the likes of iTunes) and that one of the major reasons piracy of so prevelent in the UK is the huge gap between the showing of headline programs in the US and the UK.


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