Here at Cloudflare, we frequently use and write about data in the present. But sometimes understanding the present begins with digging into the past. We recently learned of a 2024 turkmen.news article (available in Russian) that reports Turkmenistan experienced “an unprecedented easing in blocking,” causing over 3 billion previously-blocked IP addresses to become reachable. The […]
Tag Archives: research
Beyond IP lists: a registry format for bots and agents
As bots and agents start cryptographically signing their requests, there is a growing need for website operators to learn public keys as they are setting up their service. I might be able to find the public key material for well-known fetchers and crawlers, but what about the next 1,000 or next 1,000,000? And how do […]
Anonymous credentials: rate-limiting bots and agents without compromising privacy
The way we interact with the Internet is changing. Not long ago, ordering a pizza meant visiting a website, clicking through menus, and entering your payment details. Soon, you might just ask your phone to order a pizza that matches your preferences. A program on your device or on a remote server, which we call […]
Defending QUIC from acknowledgement-based DDoS attacks
On April 10th, 2025 12:10 UTC, a security researcher notified Cloudflare of two vulnerabilities (CVE-2025-4820 and CVE-2025-4821) related to QUIC packet acknowledgement (ACK) handling, through our Public Bug Bounty program. These were DDoS vulnerabilities in the quiche library, and Cloudflare services that use it. quiche is Cloudflare’s open-source implementation of QUIC protocol, which is the […]
Measuring characteristics of TCP connections at Internet scale
Every interaction on the Internet—including loading a web page, streaming a video, or making an API call—starts with a connection. These fundamental logical connections consist of a stream of packets flowing back and forth between devices. Various aspects of these network connections have captured the attention of researchers and practitioners for as long as the […]
One IP address, many users: detecting CGNAT to reduce collateral effects
IP addresses have historically been treated as stable identifiers for non-routing purposes such as for geolocation and security operations. Many operational and security mechanisms, such as blocklists, rate-limiting, and anomaly detection, rely on the assumption that a single IP address represents a cohesive, accountable entity or even, possibly, a specific user or device. But the […]
How to build your own VPN, or: the history of WARP
Linux’s networking capabilities are a crucial part of how Cloudflare serves billions of requests in the face of DDoS attacks. The tools it provides us are invaluable and useful, and a constant stream of contributions from developers worldwide ensures it continually gets more capable and performant. When we developed WARP, our mobile-first performance and security […]
State of the post-quantum Internet in 2025
This week, the last week of October 2025, we reached a major milestone for Internet security: the majority of human-initiated traffic with Cloudflare is using post-quantum encryption mitigating the threat of harvest-now/decrypt-later. We want to use this joyous moment to give an update on the current state of the migration of the Internet to post-quantum […]
Keeping the Internet fast and secure: introducing Merkle Tree Certificates
The world is in a race to build its first quantum computer capable of solving practical problems not feasible on even the largest conventional supercomputers. While the quantum computing paradigm promises many benefits, it also threatens the security of the Internet by breaking much of the cryptography we have come to rely on. To mitigate […]
A framework for measuring Internet resilience
On July 8, 2022, a massive outage at Rogers, one of Canada’s largest telecom providers, knocked out Internet and mobile services for over 12 million users. Why did this single event have such a catastrophic impact? And more importantly, why do some networks crumble in the face of disruption while others barely stumble? The answer […]
