On Sunday, 24 February 2008, in what was apparently a politically directed attempt to block YouTube, Pakistan Telecom started an unauthorized announcement of the prefix 126.96.36.199/24 – a YouTube IP – to divert local traffic away from the site. One of Pakistan Telecom’s upstream providers, PCCW Global forwarded this announcement to the rest of the Internet, which resulted in the hijacking of YouTube traffic on a global scale. The RIPE NCC Routing Information Service has published a detailed study on how this came to pass.
It seems to be generally accepted that the Border Gateway Protocol (BGP)Â is the culprit here. Read more about that protocol on Wikipedia.