The H.A.C.K.E.R. Project

Back in November of 2025, Cloudflare experienced a technical outage. While it was not the result of malicious activity, this outage had huge impacts for the world at large: many websites and other online were inaccessible during the time of this outage. But what exactly is Cloudflare, and why did this outage cause such a massive impact?

What is Cloudflare and What Do They Do?

Cloudflare is a company that manages “one of the world’s largest networks”, with one of their missions being “to help build a better Internet” (Cloudflare). Though you may not have heard of Cloudflare before, you have likely visited at least one website that is, to some degree, connected with Cloudflare. There are a lot of technical considerations and difficulties that come with hosting websites, applications, and other online media; Cloudflare helps to “ease these difficulties and empower users with the resources to make their sites, apps, and blogs safe and performant. This is done through the use of a powerful edge network that provides content and other services as close to you as possible, so you get the information as fast as possible” (Cloudflare).

In a sense, Cloudflare acts as the backbone or support for many websites and online applications. As stated by Cloudflare, “Anytime we push code, it automatically affects millions of Internet properties. Every day, thousands of new customers sign up for Cloudflare service. We serve 81 million HTTP requests per second on average. We serve data from 330 cities in over 125 countries around the world” (Cloudflare). Two of the primary jobs that Cloudflare handles are DNS services and reverse proxy services.

DNS stands for “Domain Name System”. DNS “acts as the Internet’s phonebook, translating domain names (for example, cloudflare.com) into numerical Internet Protocol (IP) addresses (for example, 103.21.244.0). The IP address is like a home address of where a website lives, and the domain name is the human-readable name” (Cloudflare). Each website has an associate IP address that serves as identifier for the website. Continuing the phonebook comparison, the IP address is like a specific person’s phone number. If you know their number, you can dial it directly and call them; for example, if you have a friend named Jenny, and know her phone number is 867-5309, you can enter “8675309” into your phone and it will ring Jenny’s phone. The same works with IP addresses. If you know a website’s IP address, you can enter that into your web browser and connect up to that website. The domain name is like having someone’s phone number in your contacts list. Instead of having to manually type in someone’s phone number, you can instead just select their name in the contacts list, and the phone will automatically call that person for you. Thus, instead of having to type in “8675309” to call Jenny, you can instead select “Jenny” in your contacts list in order to call her; you might not even remember her actual phone number after a while! In terms of websites, you can type in the website name and be brought to that website instead of having to know its IP address. The DNS is, essentially, the contacts list itself; it holds website names and what IP addresses they are associated with, making it a lot easier to navigate the web.

In a similar vein, a “reverse proxy is a network of servers that sits in front of web servers and either forwards requests to those web servers, or handles requests on behalf of the web servers” (Cloudflare). Think of a reverse proxy like an operator or receptionist at a company. Whenever you call into that company, the operator or receptionist answers your phone call, finds out who you want to reach, and either forwards your call to that person or takes a message for that person and passes it along. Not only does this help to organize network traffic, but it also “provides security by protecting Internet properties from malicious activity like DDoS attacks, malicious bots, and other nefarious intrusions” (Cloudflare). Using the operator example from above, say a scam salesman is trying to reach the CEO of a company. If they do not have the extension or a direct way to reach the CEO whenever they call in, the operator or receptionist is who answers the phone. The operator can then redirect the call to another department or handle the call as appropriate, keeping the scam salesman from ever reaching the CEO. In terms of networking, malicious bots and DDoS attacks are the scam salesmen, while the reverse proxy is the operator who prevents the attack from reaching the network (the CEO).

Why This Outage Had a Massive Impact

Since Cloudflare handles the above-mentioned resources, they help to keep a significant portion of the Internet as we know it operational. Thus, with Cloudflare going down, a lot of these services were unavailable. With DNS services unavailable, it becomes difficult, if not impossible, for a network to know which domain name (or web address, as it is sometimes called) connects to which IP address, which results in users being unable to access the website they are trying to visit, much like trying to call a friend without having their phone number saved or memorized. Similarly, with reverse proxy services unavailable, requests made by users are not able to be forwarded properly to their destination. While the scam salesman might not be able to reach the CEO, neither can legitimate business partners.

Thankfully, Cloudflare was able to mitigate this incident and restore its services within the same day that the outage began. For the full incident report, you can go here: https://www.cloudflarestatus.com/incidents/8gmgl950y3h7.

Resources & Further Reading

Cloudflare. “About Us.” Cloudflare, www.cloudflare.com/about-overview/.

—. “How Cloudflare Works · Cloudflare Fundamentals Docs.” Developers.cloudflare.com, 29 Aug. 2023, developers.cloudflare.com/fundamentals/concepts/how-cloudflare-works/.

—. “What Is Cloudflare? | Cloudflare.” Cloudflare, www.cloudflare.com/learning/what-is-cloudflare/.