In an insane, unprecedented move, Egypt shut down all internet access in the country.

How did they do it?

Gigaom has figured out the basics, but essentially you have to shut down all routers that filter incoming traffic into the country. This will take the country off the grid from the global internet.

If that's not enough, shutting down routers at ISPs will insure no one can access the web. That's pretty easy for countries that have complete control over their telecom industries.

Egypt seems to have chosen a different method. The government ordered ISPs to stop resolving addresses ending in .eg, Egypt's domain name system, in addition to sealing off outside access.

Vodafone, one of the ISPs in Egypt, released this frightening statement:

"All mobile operators in Egypt have been instructed to suspend services in selected areas. Under Egyptian legislation the authorities have the right to issue such an order and we are obliged to comply with it. The Egyptian authorities will be clarifying the situation in due course."

It boils down to this: Unless a government has direct control over ISPs, there is no "kill switch." It takes a government order to individual ISPs under the proper legal authority.