The outages appear to have stemmed from dedicated denial of service (DDOS) attacks levied against Dyn Inc., one of the world's foremost providers of internet services. The company runs domain name servers, known commonly as DNS, which provide infrastructure for internet services.
"They (DNS) work as a phone book or map to the internet, making sure that when someone writes an address into their computer or phone, it can be directed to the right place and show the right information," The Independent reported.
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Dyn confirmed that it started monitoring and fighting an attack on its infrastructure around 7 a.m. The company announced that services has been restored by 9:20 a.m.
However, a second attack was reported just before 12 p.m., again targeting Dyn's infrastructure.
"Our engineers continue to investigate and mitigate several attacks aimed against the Dyn Managed DNS infrastructure," the company said in an update posted just before 2 p.m.
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It was not immediately clear whether the attacks were related.
Dyn is based in New Hampshire; However, it provides services for multiple U.S.-based sites, and the attack on its servers caused issues loading the American sites in parts of Europe, Japan and other places, according to outage maps from Down Detector.
A DDOS attack occurs when a website gets an influx of requests meant to overload the site and make it inaccessible.