Turkey and Thailand have in the past also banned access to the site

 

Pakistan's attempts to block access to YouTube have been blamed for a near global blackout of the site on Sunday. Google, the owner of YouTube, blamed the outage on "erroneous internet protocols", sourced in Pakistan

 

BBC News has learned that the nearly two-hour long blackout was almost certainly connected to Pakistan Telecom and internet service provider PCCW.

 

The country ordered ISPs to block the video-sharing website because of content deemed offensive to Islam.

 

The BBC News website's technology editor, Darren Waters, says that to block Pakistan's citizens from accessing YouTube it is believed Pakistan Telecom "hijacked" the web server address of the popular video site.

 

Those details were then passed on to the country's internet service providers so that anyone in Pakistan attempting to go to YouTube was instead re-directed to a different address.

 

But the details of the "hijack" were leaked out into the wider internet from PCCW and as a result YouTube was mistakenly blocked by internet service providers around the world.

 

The block on the servers was lifted once PCCW had been told of the issue by engineers at YouTube.

 

A statement from Google said that the problems lasted for "about two hours".

 

"Traffic to YouTube was routed according to erroneous internet protocols, and many users around the world could not access our site," it said.

 

"We have determined that the source of these events was a network in Pakistan. We are investigating and working with others in the internet community to prevent this from happening again."

 

PCCW said it was aware of the occurrence and was "reviewing the event with the appropriate internal and external parties."

 

A leading net professional told BBC News: "This was probably a simple mistake by an engineer at Pakistan Telecom. There's nothing to suggest this was malicious."

 

IP hijacking involves taking over a web site's unique address by corrupting the internet's routing tables, which direct the flow of data around the world.

 

Cause of ban

 

Reports said Pakistan made the move because YouTube content included Danish cartoons depicting the Prophet Muhammad that have outraged many.

 

But one report said a trailer for a forthcoming film by Dutch lawmaker Geert Wilders, which portrays Islam in a negative light, was behind the ban.

 

"They [Pakistan's telecommunications authority] asked us to ban it immediately... and the order says the ban will continue until further notice," said Wahaj-us-Siraj, convener of the Association of Pakistan Internet Service Providers.

 

The government decision has caused uproar in Pakistan, according to Wahaj-us-Siraj:

 

"Users are quite upset. They're screaming at ISPs which can't do anything.

 

"The government has valid reason for that, but they have to find a better way of doing it. If we continue blocking popular websites, people will stop using the internet."

 

Other countries that have temporarily blocked access to YouTube include Turkey and Thailand.

 

http://news.bbc.co.uk/1/hi/technology/7262071.stm

Pakistan lifts the ban on YouTube

 

Turkey and Thailand have in the past also banned access to the site

 

Pakistan's telecoms regulator has lifted the restrictions it imposed on video-sharing website YouTube.

The Pakistan Telecommunications Authority has told internet service providers (ISPs) to restore access to the site, according to a spokeswoman.

 

Google, the owner of YouTube, confirmed service had been restored in Pakistan.

 

The attempt to block the site, reportedly because of a "blasphemous" video clip, caused a near global blackout of the site on Sunday.

 

A spokesman for YouTube told the BBC News website: "We are pleased to confirm that YouTube is again accessible in Pakistan."

 

It is reported that a trailer for a forthcoming film by Dutch lawmaker Geert Wilders, which portrays Islam in a negative light, was behind the restrictions.

 

The ban was instigated by Pakistan on Friday. At the time, the BBC News website's technology editor, Darren Waters, said that to block citizens from accessing YouTube it was believed Pakistan Telecom "hijacked" the web server address of the popular video site.

 

Those details were then passed on to the country's internet service providers so that anyone in Pakistan attempting to go to YouTube was instead re-directed to a different address.

 

But the details of the "hijack" were leaked out into the wider internet by Hong-Kong based provider PCCW and as a result YouTube was mistakenly blocked by other ISPs around the world.

 

The block on the servers was lifted once PCCW had been told of the issue by YouTube engineers.

 

A statement from Google said that the problems lasted for "about two hours".

 

"Traffic to YouTube was routed according to erroneous internet protocols, and many users around the world could not access our site," it said.

 

A leading net professional told BBC News: "This was probably a simple mistake by an engineer at Pakistan Telecom. There's nothing to suggest this was malicious."

 

IP hijacking involves taking over a web site's unique address by corrupting the internet's routing tables, which direct the flow of data around the world.

 

Other countries that have temporarily blocked access to YouTube include Turkey and Thailand.

 

http://news.bbc.co.uk/1/hi/technology/7262071.stm

Details emerge on YouTube block

 

Net hardware changes led to YouTube traffic hitting a dead end

 

Pakistan has rejected claims that it was responsible for blocking global access to the YouTube video clip site. YouTube was hard to reach this week following action by Pakistan to block access inside its borders for its hosting of a "blasphemous" video clip.

 

Analysis suggests the block was taken up by net hardware that routes data effectively cutting off the site.

 

But a spokeswoman for Pakistan's telecoms authority said the problem was caused by a "malfunction" elsewhere.

 

Dead end

 

"We are not hackers. Why would we do that?" Shahzada Alam Malik, head of the Pakistan Telecommunication Authority (PTA), told the AP news service.

 

The Peshawar office of the PTA issued a blocking order for YouTube last week in a bid to block access to a video clip the Pakistani government regarded as "very blasphemous".

 

Analysis by net monitoring firm Renesys shows that the problems getting through to YouTube began as a result of the action taken by Pakistan Telecom to implement the block.

 

Essentially, Pakistan Telecom took over some of the net addresses assigned to YouTube.

 

Crucially the path it offered to this group of addresses was faster than the usual one used by the hardware, or routers, that speed traffic around the internet.

 

Pakistan Telecom let this address change propagate to the routers of one of its partners - PCCW.

 

Routers are constantly in search of faster ways to get the data passing through them to its destination so news about this faster path started propagating across many of the net's routers.

 

However, because Pakistan Telecom was stopping the traffic reaching YouTube all the data reached a dead end.

 

"While it is hard to describe exactly how widely this hijacked prefix was seen, we estimate that it was seen by a bit more than two-thirds of the internet," wrote Martin Brown of Renesys in a company blog post analysing the sequence of events.

 

The problems getting through to YouTube were most severe for two hours on Sunday but the problem was cleared up soon after.

 

Access to YouTube was restored in Pakistan on Tuesday when the video clip was removed.

 

http://news.bbc.co.uk/1/hi/technology/7266600.stm