How to build your own VPN, or: the history of WARP
2025-10-29
WARP’s initial implementation resembled a VPN that allows Internet access through it. Here’s how we built it – and how you can, too. ...
Defending QUIC from acknowledgement-based DDoS attacks
2025-10-29
We identified and patched two DDoS vulnerabilities in our QUIC implementation related to packet acknowledgements. Cloudflare customers were not affected. We examine the "Optimistic ACK" attack vector and our solution, which dynamically skips packet numbers to validate client behavior. ...
So long, and thanks for all the fish: how to escape the Linux networking stack
2025-10-29
Many products at Cloudflare aren’t possible without pushing the limits of network hardware and software to deliver improved performance, increased efficiency, or novel capabilities such as soft-unicast, our method for sharing IP subnets across data centers. Happily, most people do not need to know the intricacies of how your operating system handles network and Internet access in general. Yes, even most people within Cloudflare. But sometimes we try to push well beyond the design intentions of Linux’s networking stack. This is a story about one of those attempts....
Helping protect the 2025 Moldova elections
2025-10-29
Cloudflare mitigated a 12-hour DDoS attack against Moldova's Central Election Commission, blocking over 898 million malicious requests that peaked at 324,333 requests per second. This defense kept critical election infrastructure online and accessible for citizens during a critical parliamentary vote....
State of the post-quantum Internet in 2025
2025-10-28
Today over half of human-initiated traffic with Cloudflare is protected against harvest-now/decrypt-later with post-quantum encryption. What once was a cool science project, is the new security baseline for the Internet. We’re not done yet: in this blog post we’ll take measure where we are, what we expect for the coming years, and what you can do today....
Keeping the Internet fast and secure: introducing Merkle Tree Certificates
2025-10-28
Post-QuantumResearchCryptographySecurityTLSChromeGoogleIETFTransparencyRustOpen SourceCloudflare Workers
Cloudflare is launching an experiment with Chrome to evaluate fast, scalable, and quantum-ready Merkle Tree Certificates, all without degrading performance or changing WebPKI trust relationships....
A framework for measuring Internet resilience
2025-10-28
We present a data-driven framework to quantify cross-layer Internet resilience. We also share a list of measurements with which to quantify facets of Internet resilience for geographical areas....
Announcing Workers automatic tracing, now in open beta
2025-10-28
Cloudflare Workers' support for automatic tracing is now in open beta! Export traces to any OpenTelemetry-compatible provider for deeper application observability -- no code changes required...
Online outages: Q3 2025 Internet disruption summary
2025-10-28
In Q3 2025, we observed Internet disruptions around the world resulting from government directed shutdowns, power outages, cable cuts, a cyberattack, an earthquake, a fire, and technical problems, as well as several with unexplained causes....
The tricky science of Internet measurement
2025-10-27
The Internet is one big open system composed of many closed boxes — which makes measuring the Internet difficult. In this post we explore Internet measurement as a science....
From .com to .anything: introducing Top-Level Domain (TLD) insights on Cloudflare Radar
2025-10-27
Cloudflare Radar has launched a new Top-Level Domain (TLD) page, providing insights into TLD popularity, traffic, and security. The top-ranking TLD may come as a surprise....
Data at Cloudflare scale: some insights on measurement for 1,111 interns
2025-10-27
While large cloud providers hold vast troves of passive network data, analyzing them is complicated. The scale, noise, and absence of definitive ground truth all create major hurdles. Yet by carefully quantifying these constraints and finding alternative forms of evidence, meaningful insights can still emerge....
Making the Internet observable: the evolution of Cloudflare Radar
2025-10-27
Cloudflare Radar has evolved significantly since its 2020 launch, offering deeper insights into Internet security, routing, and traffic with new tools and data that help anyone understand what's happening online....
Internet measurement, resilience, and transparency: blog takeover from Cloudflare Research and friends
2025-10-27
Coinciding with the ACM’s Internet Measurement Conference, the Cloudflare Research team is publishing a series of posts this week to share their research on building a more measurable, resilient, and transparent Internet. These posts will cover foundational concepts in Internet measurement, Internet resilience, cryptography, and networking. ...
How does Cloudflare’s Speed Test really work?
2025-10-27
In this blog post we’ll discuss how Cloudflare thinks about measuring Internet quality, how our own Cloudflare speed test works, and our future plans for providing Internet measurement tools that help everyone build a better Internet....
How Cloudflare’s client-side security made the npm supply chain attack a non-event
2025-10-24
A recent npm supply chain attack compromised 18 popular packages. This post explains how Cloudflare’s graph-based machine learning model, which analyzes 3.5 billion scripts daily, was built to detect and block exactly this kind of threat automatically....
Securing agentic commerce: helping AI Agents transact with Visa and Mastercard
2025-10-24
Cloudflare is partnering with Visa and Mastercard to help secure the future of agentic commerce....
A deep dive into BPF LPM trie performance and optimization
2025-10-21
This post explores the performance of BPF LPM tries, a critical data structure used for IP matching. ...
Load Balancing Monitor Groups: Multi-Service Health Checks for Resilient Applications
2025-10-17
Cloudflare Load Balancing now supports Monitor Groups, allowing you to combine multiple health monitors into a single, logical assessment. ...
Improving the trustworthiness of Javascript on the Web
2025-10-16
There's no way to audit a site’s client-side code as it changes, making it hard to trust sites that use cryptography. We preview a specification we co-authored that adds auditability to the web....
