YouTube Access Denied

Posted on February 25, 2008  Comments (4)

Millions of users around the globe could not access YouTube for a couple hours yesterday. Why?

Well to understand, we need to start with how you normally connect to a web site. You click on a link to Your ISP looks up the internet address for by looking at internet routing tables. Each domain has a name server that provides the IP address for where it should be found (for example, an IP address that shows is

Well what happened in this case is Pakistan decided to prevent anyone in Pakistan from accessing YouTube because the government didn’t like some video. The way Pakistan decided to accomplish this was to update their routing table to just direct all traffic that was meant to go to YouTube to a phony address which would then return nothing.

Why did many outside of Pakistan lose access to YouTube? Well their version of the routing table leaked out of Pakistan through PCCW (large internet provider), Then other internet providers adopted the incorrect information, until many around the globe were being directed to the wrong place.

You might find it amazing the routing system could allow such a thing to happen – it doesn’t seem very secure. You are right, that it doesn’t seem very sensible. When the internet was created some protocols were established that made sense then but don’t necessarily make sense for what the internet has become.

The problem was fixed when Google’s YouTube engineers contacted PCCW to inform them of the problem and have them correct it. I think if it was my site instead, I would have had difficulty figure out what was going on 🙂 Once PCCW corrected their routing tables the fixed flowed through the system and everyone was able to see the great stuff like Marissa Mayer discussing Innovation at Google.

I would imagine Internet2 (well on its way to a computer near you) and IPv6 will take not be so venerable to such a mistake.

Related: Insecure routing redirects YouTube to PakistanYouTube outage blamed on PakistanYouTube Censorship Sheds Light on Internet TrustThe Web is 15 Years OldInternet Undersea CablesHarvard Course: Understanding Computers and the InternetNet NeutralityThe Next Generation InternetThe Journey of Internet Packetsmistake proofing (the opposite of the current setup)

4 Responses to “YouTube Access Denied”

  1. No name provided
    February 26th, 2008 @ 7:11 am

    Governments blocking sites is not a new tactic on their part, but this is usually contained within that country. It is pretty scary that a scipt can so easily leak its way out of the general area it is supposed to work and into the mainstream. You are also right about the rest of us figuring that one out! Hopefully my site never gets caught up in such a position.

  2. Sam
    February 26th, 2008 @ 8:12 pm

    I think what is just as (if not more) worrying than the blanket effect of the changed IP address, is the fact that Pakistan felt it in their power to block its citizens from viewing the YouTube video in the first place. No government should ever be allowed to be in the position or to have the right to do such a thing. The govt not liking the video and then taking such action makes them seem very controlling on the one hand and very childish and petty on the other. Neither side makes them look good in my book.

  3. Ron
    February 29th, 2008 @ 12:55 am

    The Pakistanis are turning out to be like the Chinese. Ultimately whatever they are blocking will be found and heard, it just makes the topic more controversial. Whatever it is, I hope the government gets stable over there.

  4. Susan
    November 5th, 2008 @ 1:21 pm

    I was looking for this exact information, I remembered it happening but couldn’t remember when. It is worrying that the Chinese and Pakistani governments have this much power to control the views of billions of people.

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