Imagine the world without Internet. Not what the world was like before Internet, but what would happen in today’s world if the Internet suddenly went down.

How many systems today rely on the Internet to run smoothly? If the Internet were to go down, that would disrupt work, government, financial transactions, communications, shipments, travel, entertainment – nearly every aspect of modern life could be brought to a halt. If someone were able to intentionally take down the Internet, how much damage could they cause?

Cybersecurity expert, Bruce Schneier, recently wrote a post, Someone is Learning to Take Down the Internet, which highlights the increasing number of attacks focused on “probing the defenses of the companies that run critical pieces of the Internet.”

In his post, Schneier explains that someone — he suspects a large nation state like Russia or China — has been systematically testing and probing various large and important Internet companies for weaknesses. He says companies like Verisign, which registers many major web and email addresses, have seen increasing, large-scale attacks against their systems. The attackers are forcing the companies to mount various defenses in response, giving the attackers a better idea of what defense capabilities the companies have and where their defenses may be weak.

Schneier writes, “Someone is extensively testing the core defensive capabilities of the companies that provide critical Internet services. […] It feels like a nation’s military cybercommand trying to calibrate its weaponry in the case of cyberwar. It reminds me of the US’s Cold War program of flying high-altitude planes over the Soviet Union to force their air-defense systems to turn on, to map their capabilities.”

At the moment, there doesn’t appear to be much that can be done about these attacks, but at the very least, as Schneier says, “people should know.”

Read Schneier’s full article here.