Many major websites and services were unreachable for a period of Friday afternoon due to issues at Cloudflare’s 220.127.116.11 DNS service. The outage seems to have started at about 2:15 Pacific time and lasted for about 25 minutes before connections began to be restored.
We had an issue that impacted some portions of the @Cloudflare network. It appears that a router in Atlanta had an error that caused bad routes across our backbone. That resulted in misrouted traffic to PoPs that connect to our backbone. 1/2
— Matthew Prince 🌥 (@eastdakota) July 17, 2020
Cloudflare also issued a statement via email emphasizing that this was not an attack on the system.
“This afternoon we saw an outage across some parts of our network. It was not as a result of an attack,” the company said in a statement. “It appears a router on our global backbone announced bad routes and caused some portions of the network to not be available. We believe we have addressed the root cause and monitoring systems for stability now. We will share more shortly—we have a team writing an update as we speak.”
Discord, Feedly, Politico, Shopify, and League of Legends were all affected, giving an idea of the breadth of the issue. Not only were websites down but also some status pages meant to provide warnings and track outages. In at least one case, even the status page for the status page was down.
A DNS, or Domain Name System, is an integral part of the web, connecting domains (like TechCrunch.com) to their IP addresses (such as 18.104.22.168). If the one you or a site use goes down, it doesn’t matter whether a website’s own servers are working or not — users can’t even reach them in the first place. Internet providers usually have their own, but they’re often bad, so alternatives like Google’s have existed for many years, and Cloudflare launched its service in late 2018.
Cloudflare wrote in a tweet and an update to its own status page that it was “investigating issues with Cloudflare Resolver and our edge network in certain locations. Customers using Cloudflare services in certain regions are impacted as requests might fail and/or errors may be displayed.”
We are aware that some regions may be experiencing issues with some Cloudflare services. We are currently investigating.
— Cloudflare Help (@CloudflareHelp) July 17, 2020
Some of the services and sites also relied on Google’s Public DNS service (22.214.171.124), which appeared to be having simultaneous issues.
Despite much speculation as to the cause of the outage, there is no evidence that it was caused by a denial-of-service attack or any other form of malicious hackery.