Big DDoS attacks underway are causing major Internet disruptions.

Earlier this morning, Apple World Today may have been unavailable to our readers. That's because a number of large websites and web hosting providers based on the East coast of the US -- including our host Squarespace -- have been hit with a series of distributed denial of service (DDoS) attacks. The attacks are continuing, taking down such sites as the New York Times, CNN, Twitter, Netflix, HBO Now, PayPal, and Reddit. 

The attacks initially targeted DNS provider Dyn's servers at about 11 AM ET, and were mitigated by the company's countermeasures. At about 12:20 PM ET, the attacks continued and the outages are now expanding to California, Texas, Washington, and even the UK. 

The attacks are now being monitored by the United States Department of Homeland Security, and the agency is "investigating all potential causes" of the massive disruption. 

DNS providers such as Dyn resolve site names like AppleWorld.Today to IP addresses so that web browsers may communicate with servers for content delivery. A DDoS attack uses masses of hijacked PCs (usually through malware) to overwhelm the capabilities of a website or DNS provider. When users are unable to get through to a popular site, they begin refreshing it repeatedly in an attempt to load a page, which causes even more of a problem.

Even Internet backbone provider Level3 appeared to be hit, as the company's outage map (seen above) is no longer loading. Nobody seems to be sure who is making the attack or why...