The recent Stop Online Piracy Act (SOPA), considered and eventually abandoned by the US Congress after rancorous debate earlier this year, proposed giving judges the power to cut off American access to particular websites. Under the initial version of the bill, judges would have been able order Internet service providers to use only crude tools like DNS blocking to make piratical websites harder to access. The proposal was criticized strongly on grounds of practicality, due process, and free speech, but major rightsholders want such approaches implemented worldwide. In India, they have succeeded.

A Kolkata court has ordered all 387 Internet providers in the country to block a list of 104 websites after the Indian Music Industry (IMI) filed suit against them. Indian Music Industry officials filed information with the court showing that each of the 104 sites hosted at least some infringing material; the judges ruled that site blocking was a proper way of dealing with the issue. Four injunctions—on January 27, February 6, March 1, and March 2—implemented the blacklist.

Every one of the sites targeted by the music industry was ordered blocked. IMI officials have insisted to local media that they are targeting only the worst offenders, saying that they began their process with 300 websites and eventually narrowed it down to 104 of the most flagrant infringers.

As for how the blocks will be implemented, the court has allowed Internet providers three options: blocking by DNS name ("arstechnica.com"), blocking by IP address ("75.102.3.15"), or URL blocking by deep packet inspection (which can do things like block specific links like "arstechnica.com/bollywood").

But site blocking on the Internet, though it sounds so seductively easy, comes with its own set of problems. Blocking by DNS can be circumvented simply by entering a site's actual IP address instead of its name. Blocking by IP address can be bypassed by moving a site to a new server that carries a new IP address. URL blocking has little effect when an existing site simply changes its name.

These are hardly esoteric technical secrets. One of the first sites to be blocked, "songs.pk," has rebranded itself "songspk.pk." Confused users who turn to a Google search for answers will already find that link number one for "songs.pk" directs them to the new site.

Truly blocking sites from the Internet in this fashion remains difficult, though as usual the goal is more about making infringement more difficult than curtailing all illegal activity. European courts have on occasion required specific sites to be blocked, but those rulings have tended to target one site at a time, and have often been applied only to a single Internet provider. The Indian approach is far broader, and Internet companies like Facebook and Google are coming under legal pressure to censor far more material, including obscene images of gods and goddesses.

The first list of 104 sites largely focuses on regional music; it includes sites like apunkabollywood.com, bollywoodmp4.com, and lovepaki.com. IMI promises that its next targets will include more general-purpose file-sharing sites, however.

IFPI, the international music trade group, welcomed the ruling—but insisted that even such measures did not go far enough. “The court ruled that blocking is a proportionate and effective way to tackle website piracy,” said IFPI chief executive Frances Moore. "The Indian government should build on this progress by moving forward legislation to effectively tackle all forms of digital piracy to enable the country's digital music market to reach its full potential.”