FCW asks... How does a country block access to the Internet?

As Myanmar’s military cracks down on nationwide protests, the country’s ruling junta is attempting to restrict the flow of information by blocking Internet access. How can it do that?Marcus Sachs, director of the SANS Institute’s Internet Storm Center, said blocking a country’s Internet communications with the outside world is not as difficult as it might seem. Internet use among the Burmese people is limited because most access is in Internet cafes, he said. The government controls the country’s data and telecommunications networks, and Myanmar has only two Internet service providers.With those access limitations, the junta can turn Internet connections on and off at will, Sachs said. A country such as Myanmar can easily block Web access by filtering the Web server protocol TCP 80, he said, or it can physically disconnect the nation from the Internet at the point where its government-run communications networks link to gateways that connect them to other countries.The government also can block cell phone calls because they are carried over the same fiber-optic infrastructure.Could the U.S. government block Internet access in the United States? Probably not, Sachs said. The country has hundreds, if not thousands, of Internet access points that are privately owned and not under government control. Also, the number of Internet connections into and out of the United States would make it difficult for any government entity to block all of them.In countries such as Myanmar, privately owned or operated networks don’t exist, and the government controls nearly all of the physical components of Internet connectivity. However, the junta has not been entirely successful at controlling access to news of what is happening in Myanmar.Burmese citizen journalists holed up in nearby Thailand have provided a continuous news feed to the outside world. And high-tech Internet news feeds are available to people in Myanmar who might have satellite access at an embassy building.