When I lived in NYC I was really surprised to find out that most transatlantic cables terminated in this tall windowless building on Duane and Chambers street. If you basically took that building away you probably could turn off the internet for a good portion of people in the US. Or at the very least make it hard.
My point being - in Egypt there probably is a similar building that houses all of their DNS servers, lines to other countries, etc. So its not hard to believe that someone just decided to walk in and turn off the power.
In a nicely Pharaonic touch, one of the six ducts going
into the ground here is the sole property of President
Hosni Mubarak, or (presumably) whoever succeeds him as
head of state. It is hard to envision why a head of state
would want or need his own private tube full of air running
underneath the Sahara. The obvious guess is that the duct
might be used to create a secure communications system,
independent of the civilian and military systems (the
Egyptian military will own one of the six ducts, and ARENTO
will own three). This, in and of itself, says something
about the relationship between the military and the
government in Egypt.