If you had trouble accessing Twitter, Spotify, Netflix, Amazon or Reddit Friday morning, you were not alone.

A large-scale distributed denial of service attack (DDoS) on Internet performance company Dyn brought many popular sites to a standstill. The attack largely affected people on the East Coast, and by 9:30 AM ET, many sites appeared on their way back to normal.

Dyn reported the sites going down at around 11:10AM UTC, or roughly 7:10AM ET, posting on its website that it "began monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure."

In an update posted at 8:45AM ET, the company confirmed the attack, noting that "this attack is mainly impacting US East and is impacting Managed DNS customers in this region. Our Engineers are continuing to work on mitigating this issue."

An update at 9:36AM ET said that all should be back to normal.

Amazon, whose web service AWS hosts many of the web's popular destinations including Netflix, also reported East Coast issues around the same time. In an update posted at 9:36AM ET it said that it had "been resolved and the service is operating normally."

Amazon noted that it was suffering from a "hostname" issue and it was not immediately clear if it was related to the DDoS attack Dyn received.

Denial of service attacks are when someone, or a group of people, floods a particular site or service with large amounts of fake traffic in an attempt to overwhelm the system and take it offline. It was not immediately clear who initiated Friday's attack or why.

A post on Hacker News first identified the attack and named the sites that were affected. Several sites, including Spotify and GitHub, took to Twitter this morning to post status updates once the social network was back online.

Twitter users similarly took to the service to keep lists of which sites were down and comment on the situation. The term DDoS quickly vaulted to among the top of the site's list of "Trending Topics" in the United States.

"DDoS attack this morning takes out Reddit, Twitter & Spotify," wrote user @Anubis8. "Work productivity increases by 300%."

"Anyone else having a whole lot of trouble with sites loading properly this morning?," tweeted Emmy Caitlin. "Paypal is down, Twitter was down, Netflix half loading."

"Looks like Twitter is down again.....now 1 billion people won't know what I had for breakfast," commented Ben duPont.

Dyn and Amazon did not immediately respond to a request for comment.