If you've paid a visit to SoundCloud, Spotify or Twitter today, you were more than likely met with a blank screen in place of your feed. You certainly weren't the only one - DNS provider Dyn has confirmed that a distributed denial of service (DDoS) attack has resulted in dozens of websites being rendered unavailable to users.
DNS providers act as a go-between of sorts, feeding information to your browser from the corresponding IP addresses of the websites whose URLs you type in. Aside from SoundCloud, Spotify and Twitter, the overload of Dyn's directory function resulted in Box, Boston Globe, New York Times, Github, Airbnb, Reddit, Freshbooks, Heroku, Vox Media and others effectively going offline.
The attack occurred around 9:30 AM EST and appears to affect European and Asian users less than their U.S. counterparts. As this is one of the larger-scale DDoS attacks in recent memory, it's difficult to say how long it will take until technicians arrive at a solution.