Well, it was only a matter of time before what happened last Friday happened. I’m talking about the Distributed Denial of Service (DDoS) incident on server farms of a key internet firm, Dyn, that repeatedly disrupted access to major websites and online services including Twitter, Netflix,GitHub, and PayPal across the U.S. and Europe last Friday. The White House called the disruption malicious and hacker groups have claimed responsibility, though their assertion is not yet verified.

The event involved multiple denial-of-service (DoS) attacks targeting systems operated by Domain Name System (DNS) provider, Dyn, that rendered major internet platforms and services unavailable to large swaths of North America and Europe.

“The complexity of the attacks is what is making it so difficult for us,” said Kyle York, Dyn’s chief strategy officer. “What they are actually doing is moving around the world with each attack.”

As a DNS provider, Dyn provides to end-users the service of mapping an Internet domain name—when, for instance, entered into a web browser—to its corresponding IP address. The DDoS attack involved tens of millions of DNS lookup requests from a large number of IP addresses. The activities are believed to involve a botnet coordinated through a large number of IoT devices that had been infected with the Mirai malware.