Major Internet services including Twitter, Spotify and Amazon suffered service interruptions and outages on Friday as Dyn, a US Internet provider came under sustained cyber attack.
The cyber attack meant that millions of Internet users could not access the websites of major online companies such as Netflix and Reddit as the company responded to attack after attack.
"Our engineers are continuing to work on mitigating this issue," the company said on its website close to 1700 GMT.
We are continuing to mitigate a DDoS against our Managed DNS network. For more information visit our status page.
— Dyn (@Dyn) October 21, 2016
The website Gizmodo said it had received reports of difficulty at sites for media outlets including CNN, The Guardian, Wired, HBO and People as well as the money transfer service PayPal.
Dyn, which is headquartered in New Hampshire, said the attack went after its domain name service, causing interruptions and slowdowns.
I peacefully parted w/ Twitter, PayPal, and a few others temporarily. But when you mess w/ my Spotify.. not ok. DDoS pic.twitter.com/4fYgN9GD6F
— Auria P. Moore (@auriapmoore) October 21, 2016
Scott Hilton, executive vice president for products at Dyn, said in a statement Friday morning that a "global DDoS attack" had been launched on its Managed DNS infrastructure on the US east coast.
Dyn manages Domain Name Servers (DNS), which act as switchboards connecting Internet traffic.
DNS are a crucial element of Internet infrastructure, converting numbered Internet Protocol addresses into the domain names that allow users to connect to Internet sites.
Distributed denial of service (DDoS) attacks involve flooding websites with traffic, making them difficult to access or taking them offline entirely.
Attackers can use them for a range of purposes, including censorship, protest and extortion.
The loose-knit hacktivist network Anonymous in 2010 targeted the DNS provider EveryDNS among others in 2010 as retribution for denying service to the anti-secrecy organisation WikiLeaks.
Wow the DDoS took out Twitter, Reddit, Netflix, Spotify, Amazon, and Tumblr. I got so much work done I'm on track to retire by 4pm.
— Michael Cella (@mikeVcella) October 21, 2016