IPB199: Developing IPv6-Friendly Code
Tom Coffeen and Nick Buraglio welcome Chris Cummings to talk about developing code for IPv6. Chris argues that moving to IPv6 restores end-to-end connectivity, which reduces complexity for developers without the need for “ridiculous hacks” caused by IPv4 NAT. The discussion offers practical advice on avoiding common developer traps, and covers financial benefits such as... Read more »Post-quantum encryption for Cloudflare IPsec is generally available
While more than two-thirds of human-generated TLS traffic to Cloudflare is already protected by post-quantum cryptography, the world of site-to-site networking has been a different story. For years, the IPsec community remained caught between the high bar of Internet-scale interoperability and the niche requirements of specialized hardware. That gap is now closing.
Earlier this month, we announced that Cloudflare has moved its target for full post-quantum security forward to 2029, spurred by several recent advances in quantum computing. To advance that goal, we’ve made post-quantum encryption in Cloudflare IPsec generally available.
Using the new IETF draft for hybrid ML-KEM (FIPS 203), we’ve successfully tested interoperability with branch connectors from Fortinet and Cisco — meaning you can start protecting your wide-area network (WAN) against harvest-now-decrypt-later attacks today using hardware you already have.
This post explains how we implemented the new hybrid IPsec handshake, why it took four years longer to land than its TLS counterpart, and how the industry is finally consolidating around a standard that works at Internet scale.
Cloudflare IPsec is a WAN Network-as-a-Service that replaces legacy network architectures by connecting data centers, branch offices, and cloud VPCs to Cloudflare's global IP Anycast Continue reading
Agents can now create Cloudflare accounts, buy domains, and deploy
Coding agents are great at building software. But to deploy to production they need three things from the cloud they want to host their app — an account, a way to pay, and an API token. Until now these have been tasks that humans handle directly. Increasingly, agents handle them on the user’s behalf. The agent needs to perform all the tasks a human customer can. They’re given higher-order problems to solve and choose to use Cloudflare and call Cloudflare APIs.
Starting today, agents can provision Cloudflare on behalf of their users. They can create a Cloudflare account, start a paid subscription, register a domain, and get back an API token to deploy code right away. Humans can be in the loop to grant permission, but no human steps are required from start to finish. There’s no need to go to the dashboard, copy and paste API tokens, or enter credit card details. Without any extra setup, agents have everything they need to deploy a new production application in one shot. And with Cloudflare’s Code Mode MCP server and Agent Skills, they’re even better at it.
This all works via a new protocol that we’ve co-designed with Stripe as part Continue reading
Generate Partial Device Configurations with netlab
At ITNOG 10, I’ve seen something that I haven’t seen in a very long time: a mini-Interop-style physical lab using a dozen devices from different vendors. The network core was a leaf-and-spine fabric with off-path BGP route reflectors and numerous other devices attached to it.
I’ve configured a few networks in the past, so I know it must have been a beast to configure all those devices by hand (and fix all the IP addressing errors), but then a thought struck me: unless one wants to practice configuring IP addresses, it might be a good idea to use netlab to generate the IP addressing plan and partial device configurations.
Pytest for Automated Network Testing (I)
Pytest is a Python testing framework. It is primarily used by developers to test their code and make sure it behaves as expected. For example, if you write a function that adds two numbers, you can write a test to verify that the function returns the correct result. If it does, the test passes. If not, the test fails, and pytest tells you exactly where things went wrong.
That is the traditional use case, but pytest is not limited to testing code. You can use it to test anything that can be scripted in Python, and that includes testing your network.
In this series, we will use pytest to write tests that connect to network devices and verify their state. For example, we can write a test that connects to a router and checks whether BGP is up. If BGP is up, the test passes. If not, the test fails. We can also check things like interface states, routing table entries, OSPF neighbours, or really anything else you can pull from a device.
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Pytest is not the only testing framework available in Python. unittest is another popular option and is actually built into the Python standard library, so you Continue reading
D2DO301: Actually Implementing AI
Kyler and Ned are joined by Enrico Teotti, an independent consultant with over 25 years of experience. Enrico has worked with clients on real-world AI implementations, and he’s here talk about what he’s learned, including using AI to query databases, and for debugging and performance analysis. They also touch on the importance of using AI... Read more »VM Migration to Kubernetes: What Breaks and How to Prevent It
Here is what nobody putting together the business case for a VM migration to Kubernetes will tell you upfront: the compute is the easy part.
Moving workloads off vSphere and onto Kubernetes is conceptually straightforward. The tooling has matured. The architecture is proven. Compute moves, storage remaps, and the platform team has a plan.
The network is where projects quietly stall.
Not because the technology does not work. Because nobody scoped the network properly before the project started. A platform migration turned into a multi-team coordination exercise. The firewall team needed a change window. The security team needed to review a network placement that changed when it should not have needed to. The application team discovered hardcoded IPs that nobody documented.
Six months later, half the VMs are still on vSphere and the project is technically “in progress.”
This is not a skills gap. It happens at the most mature organisations with capable teams. It is a scoping problem, and it has a specific cause: the gap between how VM networking works and how Kubernetes networking works is wider than it looks on a migration plan.
This post is for the people who approve these projects. Here is what Continue reading
SONiC Part 1: SONiC Lab Setup on Windows (Step-by-Step)
Introduction
This chapter explains how to build
a SONiC virtual test environment on a Windows computer. First, we enable the
required Windows features for WSL 2 and update and verify the WSL installation.
Next, we install an Ubuntu distribution and validate that the Linux environment
is working correctly, including basic resource checks (CPU, memory, and disk).
After the Linux environment is ready, we install Docker Engine from Docker’s
official repository and complete the required post-installation steps to run
containers. We then install Containerlab, download the SONiC virtual switch
image (docker-sonic-vs.gz), copy it into WSL, and load it into Docker.
Finally, we install Visual Studio Code on Windows and connect it to WSL to make
creating and editing the YAML topology files easier. The next chapter uses this
environment to define and deploy a simple SONiC-based topology.
Phase 1: Enable Features for WSL
WSL 2 requires two Windows
features to be enabled. The first feature, Microsoft-Windows-Subsystem-Linux
(Example 1-1), enables WSL. The second feature, VirtualMachinePlatform
(Example 1-2), is required to run WSL 2.
In this
example, both features are enabled using Microsoft PowerShell (Run as
Administrator) with the dism.exe command. The options used are:
On Generating EVPN MAC/IP Routes
Naveen Kumar Devaraj was reading my Integrated Routing and Bridging (IRB) with EVPN MAC-VRF Instances lab exercise and spotted this detail:
Arista EOS originates MAC-IP routes with and without IP addresses, effectively doubling the size of the EVPN BGP table
He kindly wrote a LinkedIn comment explaining that behavior:
HW076: Linux for the WLAN Professional
What separates good Wi-Fi engineers from ones who really can troubleshoot anything? Linux. Understanding Linux—from packet capture workflows to using tcpdump to how USB NIC drivers work—will set you apart from other engineers. Guest Bryan Ward joins the show to break down why you need to know Linux as a WLAN professional and how you... Read more »PP107: Why Now’s the Time to Prepare for a Post-Quantum World (Sponsored)
A cryptographically relevant quantum computer is, at some point, going to emerge that can crack modern encryption. But we don’t know when, so it’s tempting to set this problem aside. On today’s sponsored episode, we talk about why ignoring Post-Quantum Cryptography (PQC) isn’t an effective strategy. Sponsor Cisco is here to make the case for... Read more »Shutdowns, power outages, and conflict: a review of Q1 2026 Internet disruptions
In the first quarter of 2026, government-directed shutdowns figured prominently, with prolonged Internet blackouts in both Uganda and Iran, a stark contrast to the lack of observed government-directed shutdowns in the same quarter a year prior. This quarter, we also observed a number of Internet disruptions caused by power outages, including three separate collapses of Cuba's national electrical grid. Military action continued to disrupt connectivity in Ukraine and also impacted hyperscaler cloud infrastructure in the Middle East. Severe weather knocked out Internet connectivity in Portugal, while cable damage disrupted connectivity in the Republic of Congo. A technical problem hit Verizon Wireless in the United States, and unknown issues briefly disrupted connectivity for customers of providers in Guinea and the United Kingdom.
This post is intended as a summary overview of observed and confirmed disruptions and is not an exhaustive or complete list of issues that have occurred during the quarter. A larger list of detected traffic anomalies is available in the Cloudflare Radar Outage Center. Note that both bytes-based and request-based traffic graphs are used within this post to illustrate the impact of the observed disruptions, with the choice of metric generally made based on which better illustrates the Continue reading
Worth Reading: Lab as Code (containerlab and netlab)
@sjhloco wrote an excellent in-depth description of how you can use containerlab and netlab to manage your labs as code.
He also documented a few netlab shortcomings (one of which caused a crash); fortunately, I found his blog post (admittedly over a year later) and fixed most of them in release 26.04:
NB572: Quantum Switches and Flying Cars
Take a Network Break! We start with follow up on Anthropic’s Project Glasswing and Linux 7.0. On the news side, Cisco announces a prototype quantum switch that promises to support multiple quantum encoding modalities, Cato Networks adds an enterprise browser to its security offerings, and Mozilla validates the bug-finding powers of Anthropic’s Mythos model. Anthropic... Read more »You Can’t Patch People
One of the things I’ve noticed when it comes to IT is how quickly we’re willing to use software to solve people problems. Over my career I’ve seen all manner of crazy solutions to get around people being lazy or uneducated. Remember vMotion? Or OTV for stretched layer 2? Why do you think those solutions came about? I posit that it’s because it’s faster to write software than to patch people.
Hacking Humans
I see this most often in cybersecurity. Developers love to create software solutions that prevent things from happening. Phishing and all its various forms are some of the top priorities for solutions that prevent leaking of information. While we have invested a lot in phishing tests and education it’s also very likely that there are controls in place that prevent users from accidentally giving out information to threat actors.
Why are we so willing to write software to fix problems instead of teaching people to avoid those issues? I think in part it’s because software is predictable. If I create an app or write some controls into a platform it’s going to behave the same way every time. That’s the definition of deterministic. Every time the software Continue reading