The Egyptian government has restored Internet service in the nation, ending an unprecedented five-day blockage during which the country effectively disappeared from the global network.

All five major Egyptian ISPs are back online after being shuttered Friday in an effort to quell spreading protests against President Hosni Mubarak’s 30-year reign. Social networking sites, which where were blocked before the general Internet blackout began, are also reportedly functional.

“We confirm that Facebook and Twitter are up and available inside Egypt, at least from the places we can monitor,” said James Cowie of Internet monitoring firm Renesys. “No traffic blocks are in place, DNS answers are clean, IP addresses match, no funny business. For now.”

Recent upheavals in Iran, Tunisia and Egypt have focused attention on the Internet and social networking as a tool for organizing political action. Both Iran and Tunisia blocked specific sites or enacted general Internet slowdowns in efforts to suppress dissent, but Egypt’s total blockade of Internet service was unprecedented in its scope.

During the blackout, a few Egyptians were able to get online via dial-up or satellite connections, and Google launched a service that allowed Egyptians to post to Twitter using an ordinary phone. However, the totality of the Internet shutdown rendered most efforts to circumvent it ineffective.

With President Mubarak’s announcement yesterday that he would step down, the authoritarian government’s drastic actions appear to have been in vain.

The Egyptian Internet crisis has also drawn attention to proposed Senate bills that would grant the White House authority to shut down parts of the American Internet and disconnect private computers in response to cyber-security threats.

The Internet “kill-switch” bill was introduced last December through the Homeland Security Senate committee but expired with the new Congress. But in the wake of the Egyptian unrest, debate has surged over government controls over the Internet in political emergencies and the role that mobile and social networking technology plays in the democratic process.