On Friday, many popular sites on the internet--Spotify, Twitter, Reddit, Amazon, and dozens of others--were temporarily shut down due to a massive distributed denial of service (DDoS) attack on servers hosted by Dyn, a host utilized by many major websites.
Domain Name Servers (DNS) act as the Internet’s phone book. Basically, they facilitate your request to go to a certain webpage and make sure you are taken to the right place. If the DNS provider that handles requests for Twitter is down, well, good luck getting to Twitter. Some websites are coming back for some users, but it doesn’t look like the problem is fully resolved.
Dyn posted this update on its website: “Starting at 11:10 UTC on October 21th-Friday 2016 we began monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure. Some customers may experience increased DNS query latency and delayed zone propagation during this time. Updates will be posted as information becomes available.”
The attack was first reported before 9:00 a.m. ET, and was resolved around 9:45 a.m. ET. It is unknown who--or what--was behind the attack.