In the last few days, I decided to check out how much better ChatGPT has gotten in the last year or two. I tried to be positive and was rewarded with some surprisingly good results. I even figured out I can use it to summarize my blog posts using prompts like this one:
Using solely the information from blog.ipspace.net, what can you tell me about running ospf over unnumbered interfaces
And then I asked it about unnumbered interfaces and IS-IS, and it all went sideways:
Today, organizations struggle managing disparate technologies for their Kubernetes networking and network security needs. Leveraging multiple technologies for networking and security for in-cluster, ingress, egress, and traffic across clusters creates challenges, including operational complexities and increased costs. For example, to manage ingress traffic for Kubernetes clusters, users cobble together multiple solutions from different providers such as ingress controllers or gateways and load balancers for routing traffic, as well as Web Application Firewalls (WAFs) for enhanced security.
Despite the challenges it brings, deploying disparate technologies has been a “necessary evil” for organizations to get all the capabilities needed for holistic Kubernetes networking. Here, we’ll explore challenges this proliferation of tooling introduces, and provide actionable tips for today’s platform and security teams to overcome these issues.
The fragmented approach to networking and network security in Kubernetes leads to challenges and inefficiencies, including:
Continuing the discussion started by my Breaking APIs or Data Models Is a Cardinal Sin and Screen Scraping in 2025 blog posts, Dr. Tony Przygienda left another thoughtful comment worth reposting as a publicly visible blog post:
Having read your newest rant around my rant ;-} I can attest that you hit the nail on the very head in basically all you say:
For EVPN/VXLAN, Type 5 routes are used for two purposes: Internally and Externally
Internally it’s used to communicate which VTEPs have a given subnet instantiated on it.
Here’s an example of the output of the command show ip bgp route-type ip-prefix ipv4 on an Arista cEOS spine running EVPN/VXLAN.
It’s showing you that 10.1.10.0/24 (VLAN 10/VNI 10010) is only available on leaf1 and leaf2 (10.1.255.1-2) and 10.1.20.0/24 (VLAN 20/VNI 10020) is only available on leaf3 and leaf4 (10.1.255.3-4). It’s eBGP so each leaf has its own ASN (you see in the path field). The next hop shows the VTEP IP (10.1.254.1-4). I checked on the spine as the spine receives all the EVPN routes from the leafs and propagates them as a route server. The spines don’t install any of these routes, they just propagates them.
Network Next Hop Metric LocPref Weight Path
* > RD: 10.1.255.1:10000 ip-prefix 10.1.10.0/24
10.1.254.1 - 100 0 65101 i
* > RD: 10.1.255.2:10000 ip-prefix 10.1.10.0/24
10.1.254.2 - 100 0 65102 i
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For the third consecutive year, Gartner has named Cloudflare in the Gartner® Magic Quadrant™ for Security Service Edge (SSE) report. This analyst evaluation helps security and network leaders make informed choices about their long-term partners in digital transformation. We are excited to share that Cloudflare is one of only nine vendors recognized in this year’s report. You can read more about our position in the report here.
What’s more exciting is that we’re just getting started. Since 2018, starting with our Zero Trust Network Access (ZTNA) service Cloudflare Access, we’ve continued to push the boundaries of how quickly we can build and deliver a mature SSE platform. In that time, we’ve released multiple products each year, delivering hundreds of features across our platform. That’s not possible without our customers. Today, tens of thousands of customers have chosen to connect and protect their people, devices, applications, networks, and data with Cloudflare. They tell us our platform is faster and easier to deploy and provides a more consistent and reliable user experience, all on a more agile architecture for longer term modernization. We’ve made a commitment to those customers to continue to deliver innovative solutions with the velocity and resilience Continue reading
Ethan Banks created an excellent introductory Netlab - Automate Your Network Labs With YAML! video showing how easy it is to start and configure a container- or VM-based lab, and explaining the basic netlab commands you need to get started.
Thanks a million!
P.S.: If you’ve done something similar and I haven’t noticed it, please send me the link.
On April 11, 2025 09:20 UTC, Cloudflare was notified via its Bug Bounty Program of a request smuggling vulnerability in the Pingora OSS framework discovered by a security researcher experimenting to find exploits using Cloudflare’s Content Delivery Network (CDN) free tier which serves some cached assets via Pingora.
Customers using the free tier of Cloudflare’s CDN or users of the caching functionality provided in the open source pingora-proxy and pingora-cache crates could have been exposed. Cloudflare’s investigation revealed no evidence that the vulnerability was being exploited, and was able to mitigate the vulnerability by April 12, 2025 06:44 UTC within 22 hours after being notified.
The bug bounty report detailed that an attacker could potentially exploit an HTTP/1.1 request smuggling vulnerability on Cloudflare’s CDN service. The reporter noted that via this exploit, they were able to cause visitors to Cloudflare sites to make subsequent requests to their own server and observe which URLs the visitor was originally attempting to access.
We treat any potential request smuggling or caching issue with extreme urgency. After our security team escalated the vulnerability, we began investigating immediately, took steps to disable traffic to vulnerable components, and deployed Continue reading
Hendrik left an interesting comment on my Running IS-IS over Unnumbered Ethernet Interfaces blog post:
FRRouting (Linux) with pure IS-IS, the only way it currently (10.3) works is to copy the loopback IPv4 address to the interfaces that you need to do IPv4 routing on. The OpenFabric (IS-IS “extension” draft) does support true unnumbered interfaces and routes IPv6.
Let’s unpack this. There are (at least) four reasons a router needs an address associated with an interface1:
Calico provides a unified platform for all your Kubernetes networking, network security, and observability requirements. From ingress/egress management and east-west policy enforcement to multi-cluster connectivity, Calico delivers comprehensive capabilities. It is distribution-agnostic, preventing vendor lock-in and offering a consistent experience across popular Kubernetes distributions and managed services. Calico eliminates silos, providing seamless networking and observability for containers, VMs, and bare metal servers, and extends effortlessly to multi-cluster environments, in the cloud, on-premises, and at the edge.
With the recent release of Calico Open Source 3.30, we added:
The Internet relies on the Border Gateway Protocol (BGP) to exchange IP address reachability information. This information outlines the path a sender or router can use to reach a specific destination. These paths, conveyed in BGP messages, are sequences of Autonomous System Numbers (ASNs), with each ASN representing an organization that operates its own segment of Internet infrastructure.
Throughout this blog post, we'll use the terms "BGP routes" or simply "routes" to refer to these paths. In essence, BGP functions by enabling autonomous systems to exchange routes to IP address blocks (“IP prefixes”), allowing different entities across the Internet to construct their routing tables.
When network operators debug reachability issues or assess a resource's global reach, BGP routes are often the first thing they examine. Therefore, it’s critical to have an up-to-date view of the routes toward the IP prefixes of interest. Some networks provide tools called "looking glasses" — public routing information services offering data directly from their own BGP routers. These allow external operators to examine routes from that specific network's perspective. Furthermore, services like bgp.tools, bgp.he.net, RouteViews, or the NLNOG RING looking glass offer aggregated, looking glass-like lookup capabilities, drawing Continue reading