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Music and movie moguls must try harder in their war against file sharing

Analysis Targeting IP addresses will not be enough anymore
Fri May 06 2011, 16:29
Tangled cables

COMMON SENSE finally prevailed this week when a US District Judge ruled that an IP address does not identify an individual person.

For years companies such as the shamed law firm ACS:Law sent threatening letters to individuals alleging that they were distributing copyrighted content over the internet. That racket hinged on the law firms getting details from internet service providers (ISPs) to provide information on the customer behind the IP address, on the gross assumption that an IP address is a unique identifier that conclusively points to a specific person or household.

Tech-literate computer users were quick to correctly point out that thanks to network address translation (NAT), more than one computer can be represented by an IP address, and that local WiFi networking can be shared.

So it stands to reason that if more than one computer can have the same 'public facing' IP address, it can be possible that more than one individual is represented by a single IP address. That common sense argument had been ignored in courts of law, that is until US District Judge Harold Baker ruled that a "disconnect between IP subscriber and copyright infringer" might exist in some cases.

Some internet users had claimed that because their ISPs provided them with an IP address that changes every so often that it was not possible to accurately identify them. Dynamic IP addresses might not be tied to a particular account, however ISPs can easily find out what IP address was allocated to a particular account at a specific time. And pointing to the proliferation of WiFi networks only partially explains the problems with so-called IP to ID mapping.

The real layer of obfuscation that has managed to catch out law enforcement authorities is NAT. The physical connection layer certainly affects whether unauthorised people can be part of a particular network, but even on wired networks, the use of NAT allows for the possibility that more than one person is represented by a single IP address.

However the biggest surprise with Judge Baker's ruling should be reserved for why it took so long for the courts to come to this decision, and he should be given credit for ultimately improving the way law firms go about accusing people of copyright infringement.

Judge Baker didn't hold back on what he thought about the practice of IP to ID mapping, saying, "Where an IP address might actually identify an individual subscriber and address the correlation is still far from perfect". He cited an MSNBC article that reported a story about an innocent man who was accused of peddling pornography after leaving his WiFi network unsecured.

Judge Baker continued, "The infringer might be the subscriber, someone in the subscriber's household, a visitor with her laptop, a neighbour, or someone parked on the street at any given moment." This might all be obvious to anyone who has actually set up a wireless network, but now thanks to Judge Baker it is a matter of public record and can be used as a defence.


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