Yak-Shaving netlab Podman Support

Long, long time ago, in a long-forgotten PR adding support for Cumulus VX Ignite runtime, an off-the-cuff remark was made saying, “and this is how you use netlab with Podman”. That remark was quietly sitting in the documentation for years until someone (A) tried to use Podman and (B) found enough time to report that it doesn’t work with netlab.

I don’t know what that tells us: either very few people use Podman, or nobody (apart from a notable exception) cares enough to spend a few minutes telling us stuff doesn’t work1.

Anyway, based on Joey Buiteweg’s wonderful research, I was able to put together a working solution pretty quickly, but it did involve a lot of yak shaving (more bovine details).

Read more …

Dear Junos, Tunnels Are Not Virtual Links

In late June, we added GRE tunnels to netlab, including a Junos implementation. It looked great (as in “everything worked”) until I changed the integration tests to have GRE tunnels between a tested device and a pair of FRR containers. All other implementations worked as before, but Junos failed to establish an OSPFv3 adjacency over the GRE tunnel with FRR.

Stefano Sasso quickly identified the culprit: Junos OSPFv3 process thinks it should send the DBD packets over GRE tunnels with MTU set to zero (the behavior reserved for virtual links)1.

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Testing DDoS mitigation software

The recently released open source sflowgen tool is a synthetic sFlow generator intended for testing, demonstrations, dashboards, and attack-detection validation. This article uses sflowgen to test the DDoS Protect application.

The screen capture shows how sflowgen DDoS attack telemetry appears in the DDoS Protect dashboard. Charts in the dashboard show different types of DDoS attack. You can see normal low level background activity below the red horizontal threshold line. DDoS traffic can be seen ramping up on the udp_flood and ip_flood charts and leveling off once the attack reaches maximum intensity. Notice that as soon as the attack traffic crosses the threshold, the Controls chart indicates that a Pending control has been created to mitigate the attack.

The Controls table shows the udp_flood attack against host 10.10.0.42 using port 443 as the attack vector. In this case the control action is set to drop, i.e. use a Remotely Triggered Black Hole (RTBH) as the mitigation action. The pending status indicates that it is waiting for user confirmation before being applied.

The Settings tab has been configured to add a local address group containing the 10.10.0.0/24 and 2001:db8:10::/64 CIDRs used in the default Continue reading

HW086: High Density Wi-Fi Part 2

By popular demand, Keith is joined once again by Ferney Muñoz and Tom Hildebrand to answer listener questions and to dive deeper into designing high-density Wi-Fi for large-scale events. Together they share practical insights on managing DHCP scopes, the realities of client isolation, and more.

The Cloudflare Blog – Brought to you by EmDash

You likely noticed the recent redesign of the Cloudflare Blog. We added dark mode, modernized the look and feel, and made a lot of other small improvements along the way.

What you might not have noticed – well, except for those who are more terminally online – is that the redesign was part of a much bigger migration project. On Wednesday, August 12, we moved the blog to EmDash, a content management system (CMS) built especially to work on Astro and with Cloudflare.

We’ll take you into the migration story – what we learned and how EmDash got better – as well as into the benefits we’re already seeing from a new platform.

We are Customer Zero

At Cloudflare, Cloudflare itself is Customer Zero. This means that we use our products. And – in use – we make them better for ourselves and our customers.

This is a very real cultural value at Cloudflare. The burden of proof is on you if you want to use an external vendor. Why can’t that team support you, what gaps are there, why can’t those gaps be filled, and are those “gaps” true requirements?

This preference is even enshrined in our internal Continue reading

NB588: Active Threats Target Siemens PLCs; IBM Chills Qubits With Modular Cryogenics

Take a Network Break! It’s a Red Alert double feature for Oracle’s Internet Directory LDAP server and Cisco’s Secure Workload Software. In tech news, US law enforcement and intelligence agencies release a joint advisory warning of active threats against Siemens PLCs, Marvell wins a deal to make chips for Google that could bring billions in... Read more »

An interactive introduction to the spanning tree protocol

Warning

This post contains interactive examples. To visualize and interact with them, you need to leave your RSS reader.

Imagine you rent office space for a three-day event. You quickly set up a few Ethernet switches and tape some cables on the floor to get everyone online. Unfortunately, Stan, your clumsiest coworker, kicks out a cable every time he gets up for coffee. You could add extra cables, but then you’d get a broadcast storm: Ethernet packets that loop and multiply until nothing else gets through.

That’s where the spanning tree protocol (STP) comes in. STP blocks just enough of your spare cables to leave a loop-free tree. When Stan strikes again, it rebuilds the tree in a second, leaving some time for Blobby, your one-person support crew, to reconnect the cable. See for yourself: the diagram below runs a real STP implementation in your browser!

:demo

A1 @0,0 prio=4096
A2 @0,1
A3 @0,2
A4 @0,3

B1 @1,0 prio=8192
B2 @1,1
B3 @1,2
B4 @1,3

C1 @2,0 prio=8192
C2 @2,1
C3 @2,2
C4 @2,3

A1 -- A2 hazard=0
A2 -- A3 hazard=0
A3 -- A4 hazard=0
B1 -- B2
B2 -- B3
B3 -- B4
C1 -- C2  Continue reading

A non-interactive introduction to the spanning tree protocol

Imagine you rent office space for a three-day event. You quickly set up a few Ethernet switches and tape some cables on the floor to get everyone online. Unfortunately, Stan, your clumsiest coworker, kicks out a cable every time he gets up for coffee. Spare cables would fix that, but a loop turns into a broadcast storm: Ethernet packets multiply until nothing else gets through. That’s where the spanning tree protocol comes in: it blocks just enough of the spare cables to leave a loop-free tree, and rebuilds it in a second each time Stan strikes again.

This content is also available as a text version, with interactive demos that run a real implementation directly in your browser!

This video is an experiment.1 Honestly, except for Radia Perlman reading her poem,2 you should read the original article instead. It presents the same content, but you can play with the interactive examples, which are the main contribution. On the other hand, if you happen to like the video, be sure to tell me in the comments!

  1. I thought automated tools would produce this video in a couple of hours. In the end, it was another rabbit hole Continue reading

AI Red Team Agents Automate Attacks on your AI Agents. Runtime Policies Automate their Defense.

The AI red teaming market grew up fast this year. OpenAI bought Promptfoo, Cisco and Microsoft shipped automated attack suites, and a seed-stage startup publicly compromised 50 of 55 live customer service bots. These platforms find real problems at a scale no human team can match. But when you read the findings closely, a pattern emerges: agents talked into refunds, transfers, and data leaks they had standing authority to perform. Patching the prompt fixes one phrasing until the next model update. Constraining the authority fixes the class. The first job belongs to a red team platform. The second belongs to your runtime, and no scanner will do it for you.

In April 2026, General Analysis raised a $10M seed round on the strength of an uncomfortable demonstration: its adversarial agent attacked 55 live customer service bots and compromised 50 of them. Not lab models, but live systems with real customers and real tool access. This post is about the market behind that demonstration: who now automates the attacker’s role, what the attacks keep finding, and why the fix that lasts is runtime policy rather than a better prompt.

What an AI red team agent actually does

A traditional red team Continue reading

SONiC Deep Dive: BGP Unnumbered for IPv4

 

Chapter 6: BGP Unnumbered for IPv4

 

Introduction

 

This chapter explains how an IPv6-only transport network can provide connectivity between IPv4 networks by using IPv6 link-local addresses as next-hop addresses for IPv4 routes.

The first part of the chapter starts by showing how to configure interfaces to enable IPv6 and automatically generate IPv6 link-local addresses. These addresses can then be advertised to IPv6 peers using Router Advertisement (RA) messages defined by the IPv6 Neighbor Discovery Protocol (NDP). This provides the IPv6 link-local addressing required to establish BGP Unnumbered peering. Because the focus of the book is SONiC NOS, this section also shows how locally configured, interface-specific IPv6 information, as well as information received from neighboring devices, is represented in the SONiC Redis databases.

The second part of the chapter introduces how to configure external BGP peering using IPv6 link-local addresses without explicitly specifying the neighbor's IPv6 address or ASN. This simplifies automation by reducing the number of switch-specific configuration parameters. As in the first part, we examine the relevant Redis database tables after configuration and verification.

Figure 6-1 depicts the example topology used in this chapter. The physical topology is based on two-tiers Clos topology, with a single Continue reading

Arista cEOS Does Not Apply ACLs to Control-Plane Traffic

When someone starts singing the Use Digital Twins to Test Your Network hymn (or, more recently, tells you how AI agents can do that to validate their ideas), ask them about these minor details. If they persist, point them (not that it would help) to this long list of gotchas.

That list just got longer: Arista cEOS container does not apply inbound ACLs to control-plane traffic (Arista vEOS VM does).

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Fakta Unik Denman Cryobrine Corridor di Danau Lake Denman

Danau Lake Denman Basal Cryobrine Corridor merupakan salah satu fenomena alam yang semakin menarik perhatian para ilmuwan dan peneliti dalam beberapa tahun terakhir. Fenomena yang sering disebut dengan istilah denman cryobrine corridor ini merupakan bagian penting dalam studi iklim dan ekosistem ekstrem di Bumi. Artikel ini akan mengupas fakta-fakta unik seputar denman cryobrine corridor yang relevan hingga saat ini dan bagaimana keberadaannya memengaruhi riset ilmiah di berbagai disiplin ilmu.

Pendahuluan: Apa Itu Denman Cryobrine Corridor?

Denman cryobrine corridor adalah sebuah bagian unik dari sistem glester di sekitar Danau Lake Denman yang dikenal dengan kandungan air garam yang tinggi pada suhu yang sangat rendah. Fenomena ini muncul ketika air garam superdingin membentuk sebuah koridor alami di bawah permukaan es. Keunikan dari denman cryobrine corridor terletak pada kemampuan air garam tersebut bertahan dalam kondisi ekstrem tanpa membeku, sehingga menimbulkan potensi ekosistem mikroorganisme unik yang belum banyak dipahami oleh ilmu pengetahuan.

Saat ini, denman cryobrine corridor sangat menjadi fokus riset karena memberikan wawasan baru terkait adaptasi kehidupan di kondisi ekstrem hingga potensi eksplorasi astrobiologi di planet lain yang memiliki kondisi serupa, seperti Mars atau bulan-bulan es di tata surya.

Karakteristik Fisik Denman Cryobrine Corridor

Pada periode terbaru, penelitian menggunakan satelit dan teknologi bawah Continue reading

Misteri Fenomena Clearwater West Shock Vein Zone yang Menarik

Fenomena alam geologi menarik perhatian para ilmuwan dan penggemar sains di seluruh dunia, salah satunya adalah kawasan Clearwater West Shock Vein Zone. Hingga saat ini, fenomena tersebut masih menyimpan banyak misteri yang membuat para peneliti terus mendalaminya. Artikel ini akan membahas secara lengkap dan terbaru tentang fenomena Clearwater West Shock Vein, dari penemuan, karakteristik, hingga implikasi ilmiah dan lingkungan yang relevan pada kondisi saat ini.

Pendahuluan: Apa Itu Clearwater West Shock Vein?

Fenomena Clearwater West Shock Vein merupakan sebuah zona nirkon yang ditemukan di kawah Clearwater West, salah satu dari dua kawah yang saling berdekatan di Quebec, Kanada. Fenomena ini dikenal sebagai salah satu contoh nyata dari struktur geologi yang terbentuk akibat benturan meteorit raksasa ke permukaan bumi. Kawah Clearwater West sendiri membentang sekitar 26 kilometer dan dikenal sebagai salah satu situs krater tipe “dual impact” yang unik.

Zona shock vein atau urat kejut adalah lapisan tipis material yang terbentuk dengan pola patahan dan deformasi ekstrem karena tekanan dan suhu sangat tinggi pada saat terjadi benturan meteorit. Wilayah Clearwater West Shock Vein menjadi sangat penting sebagai lokasi studi untuk memahami lebih jauh mekanisme pembentukan material dan batuan akibat benturan luar angkasa.

Penemuan dan Studi Terkini di Kawah Clearwater West Continue reading

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