AP Photo/Connie Zhou

Internet users around the world, but mostly in the US, reported that some top websites were not loading on Friday morning.

The affected sites include Amazon, Twitter, Netflix, Etsy, Github, and Spotify.

The issue is currently ongoing.

It was mostly resolved at 9:20 a.m. ET, but at 12:07 p.m. ET, the issue started to crop up again, according to one of the companies at the center of the apparent cyber attack. 

The issue appears to have something to do with DNS hosts — in particular, Dyn, one of the biggest DNS companies.

Domain Name Servers are a core part of the internet’s backbone. They translate what you type into your browser —www.businessinsider.com, for example — into IP addresses that computers can understand.

Dyn said on Friday that it suffering a DDoS attack, or a distributed denial of service. That basically means hackers are overwhelming Dyn’s servers with useless data and repeated load requests, preventing useful data — the Twitter IP address, for example — from getting through.

No group has taken credit for the DDoS attack yet. The Department of Homeland Security is monitoring the attack, Politico’s Eric Geller reports. 

The second round of attacks seems to effect the West Coast of the US and Europe as well. If you’re having issues, one way to address the issue is to switch the DNS servers your computer looks for to those maintained by OpenDNS.

Here’s a walkthrough and here’s Apple’s support page. 

Here’s how the day has unfolded, according to Dyn, the company being attacked. 

7:10 a.m. ET: 

“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.”

8:45 a.m. ET:

“This attack is mainly impacting US East and is impacting Managed DNS customer in this region. Our Engineers are continuing to work on mitigating this issue.”

9:36 a.m. ET: 

“Services have been restored to normal as of 13:20 UTC.”

 As of 12:06 p.m. ET, the attack had returned:

“As of 15:52 UTC, we have begun monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure. Our Engineers are continuing to work on mitigating this issue.”

12:48 p.m. ET: 

“This DDoS attack may also be impacting Dyn Managed DNS advanced services with possible delays in monitoring. Our Engineers are continuing to work on mitigating this issue.”

1:53 p.m. ET: 

“Our engineers continue to investigate and mitigate several attacks aimed against the Dyn Managed DNS infrastructure.”

2:23 p.m. ET: 

“Dyn Managed DNS advanced service monitoring is currently experiencing issues. Customers may notice incorrect probe alerts on their advanced DNS services. Our engineers continue to monitor and investigate the issue.” 

2:52 p.m. ET: 

“At this time, the advanced service monitoring issue has been resolved. Our engineers are still investigating and mitigating the attacks on our infrastructure.”

CNBC reported that Amazon investigated the issue as well. “Amazon & DynDNS investigating internet outage reports on east coast of U.S. amid reports of major websites not working properly,” it somehow tweeted.

Earlier this month, the United States transferred its oversight of DNS to an international non-profit group, a move that had been more than 20 years in the making. 

Here’s a map of reported outages as of 9:20 a.m. ET, via Down Detector:

Level3/Down Detector

Here’s a map of reported outages as of 2:16 p.m. ET:

Down Detector

According to Hacker News and reports, some of the sites affected include:

- DYN

- Twitter

- Etsy

- Github

- Soundcloud

- Spotify

- Heroku

- Pagerduty

- Shopify

- Okta

- Zendesk

- Business Insider