18/10/2018 2:03 PM IST | Updated 18/10/2018 2:03 PM IST

How Pakistan Once Took YouTube Down For Everyone In The World For An Hour

Wednesday’s hour-long YouTube outage has happened before, and the last time something like this took place, it was done accidentally by Pakistani censors.

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KIEV, UKRAINE - 2018/08/14: YouTube social networking website seen displayed on a smart phone. (Photo by Igor Golovniov/SOPA Images/LightRocket via Getty Images)

BENGALURU, Karnataka—The hour-long global YouTube shutdown on Wednesday is a rare instance of the service shutting down for users all over the world. The temporary blip in Youtube's endless roll of video, which makes it the second-largest search engine in the world (after its elder sibling, Google), led to a sudden spike in search traffic for Vimeo (a well known video streaming platform), and yes, a 21 percent increase in viewers on PornHub — one of the world's largest repositories of pornography.

The cause of this latest YouTube outage has not been revealed yet, but this kind of failure has happened once before—when a Pakistani Internet Service Provider (ISP) in Pakistan, ordered to censor specific videos on YouTube (trailers for an anti-Islamic film by a Dutch politician), accidentally took down the entire website — not just for the people of Pakistan, but for the entire planet — in a ham-handed attempt to censor a YouTube trailer for a film that some found to be anti-Islamic.

The way it worked should have been simple. According to a Wired report, the ISP Pakistan Telecom changed its local address book for YouTube, so it could redirect users trying to visit the page on YouTube where the page that was being censored could be found. Instead, users would be sent to a "block" page which explained that the page was not available.

Unfortunately, rather than just making the change to its own lists, the ISP unintentionally sent it upstream to the rest of the Internet as well. And the change was implemented without being verified, with everyone in the world who wanted to visit YouTube instead being redirected to the block page. This took YouTube offline, and the sudden, global deluge of traffic also choked the ISP.

This isn't a normal practice though, and part of the fault lay in a Hong Kong-based company called PCCW which provides the Internet uplink to Pakistan Telecom. CNet had reported that while most large providers would have verified and stopped the misleading address, PCCW had not done this.

Of course, the problem was soon detected and the workaround fixed, and this week's outage is not likely to have followed a similar path. However, that doesn't mean that Internet issues such as these won't take place again.