Two thirds of the world lost access to Youtube yesterday because Pakistan's internet censors lost control of their censorship tools and applied them globally.
Pakistan is one of the many countries that censors websites by publishing bad "routes" to them, using national firewalls to advertise bogus pathways that computers should use to reach the banned sites; when computers try to take these routes, they reach a dead end, and thus their users can't gain access to banned sites.
The protocol for publishing internet routing information is designed to propagate from one computer to the next -- this is part of how the internet recovers from damage or malfunctions in backbone infrastructure -- and so careless censors can accidentally push poisoned routing information beyond their national borders.
Pakistan's censors ordered 70 ISPs to block Youtube over a trailer for an upcoming movie by the Dutch authoritarian islamophobe Geert Wilders. One or more ISPs messed up its routing table, and, according to Renesys Corp, who monitors internet routing data, more than two thirds of the world lost access to Youtube as a result.
China's national censors have previously cut off worlwide access to sites that were banned in China, and while they blamed this on operator error, many in the global network infrastructure community believed that it was a veiled threat or demonstration of power by China.
Pakistan Telecom established a route that directed requests for YouTube videos from local Internet subscribers to a "black hole," where the data was discarded, according to Renesys. Pakistan Telecom's mistake was that it then published that route to its international data carrier, PCCW Ltd. of Hong Kong, Underwood said.
The second mistake was that PCCW accepted that route, Underwood said. It started directing requests from its customers for YouTube data to Pakistan. And since PCCW is one of the world's 20 largest data carriers, its routing table was passed along to other large carriers without any attempt at verification.
Pakistan causes YouTube outage for two-thirds of world [Peter Svensson/ABC]
(Thanks, @dontbenebby!)
