In response to increasing civil unrest, the Egyptian government appears to have disabled almost all Internet connectivity with the rest of the world. The Internet's global routing table, which is used by Internet routers to determine where to send traffic, has had virtually every Egypt-bound route withdrawn, giving the Internet traffic no path either into or out of the country.

The routes were all withdrawn almost simultaneously last night, causing the country's Internet users to disappear over the space of about half an hour. The block appears to affect Egypt's four largest ISPs, responsible for most of the country's Internet connectivity: Link Egypt, Vodafone/Raya, Telecom Egypt, and Etisalat Misr.

Indications are that, at the time of writing, not every ISP has been taken offline. Noor Group, a smaller provider, still appears to have external connectivity, and limited sites including the Egyptian Stock Exchange appear to remain accessible. Whether this is by design or by accident is unknown. Connectivity through Egypt appears unaffected. A number of fiber-optic routes linking Europe to Asia go through Egypt, and they remain operational.

This move—the near-complete removal of a country's routes from routing tables and the resultant inaccessibility—seems quite unprecedented. Civil unrest in Tunisia earlier this year was met with limited censorship of certain sites, and similar unrest in Iran in 2009 resulted in substantial throttling (but not outright blocking) of Internet traffic. Egypt's response appears to be a great deal more heavy-handed.