DENOG17

Every now and then, I see people do some pretty odd things when trying to troubleshoot network issues. Like using curl to test a domain name right after DNS resolution failed. Or jumping into a random GitHub issue because it mentions IPv6—so it must be the same problem. Or offering troubleshooting advice that's fine in general, but has nothing to do with the actual issue.

I've run a few troubleshooting trainings before, and honestly… I didn’t love them. They were always aimed at experienced network folks, but I kept finding myself going back to explain the basics.

So this time, let’s flip the script: I’ll walk through the fundamentals first, show how things connect, and then walk you through how I solved some real-world problems I’ve seen in the wild.

Expect plenty of live demos (mostly Linux-based), and if the group size allows, you’ll get your hands dirty in some labs too.

Oh, and fair warning: I’m going to say the word “documentation” a lot. You’ve been warned.

Want to perform the bgp handshake in real life based on a realistic topology? We got you covered ... in this workshop for intermediates we will dive into some network basics of bgp driven networks and also explore route filtering best practices (mainly for the DfZ = default free zone).

After some theory every attendee will receive one network node to configure. The fellow participants will be your peers. You will depend on the peers to reach your goals.

Teams work together in small groups. One group either jointly manages an AS consisting of 3 routers and a customer downlink router or the IXP infrastructure based on EVPN with additional route server. Troubleshooting takes place across groups in order to verify the corresponding availability within the lab topology.

Warning: You will have to socialise with the peers around you!

Topics Covered:
* - TO BE DEFINED

Technologies Covered:
* - TO BE DEFINED

Pre-requisites:
Participants must have technical hands on experience of routers.
Network Fundamentals, user level UNIX and maybe some system administration,
some use of network design preferably TCP/IP-based is also helpful.
Ideally, you should already have some experience with EOS or a comparable CLI.

Workshop about the basics of BGP. Topics include:

• Prefixes and Autonomous Systems
• Why you also need an IGP (like OSPF, IS-IS)
• iBGP: BGP within your network
• eBGP: Talking to your neighbours
• Multihoming and Peering
• BGP Best Path Selection
• Bonus-Topics, if time permits:
  • BGP Communities
  • BGP Security

Lab experiments will be done using FRRouting, so participants do need a laptop. No special software is needed.

This beginner-level workshop aims to teach participants how to use containerlab as a network labbing and testing tool, and showcases both simple and complex network infrastructures that can be modelled with it. During the workshop, participants will build a simple virtual EVPN-VXLAN datacenter network and set up network telemetry collection using open-source tools. As a closing task, we will show of how a Kubernetes-based network orchestration and telemetry collection system works with the same topology that the participants have put together.

This hand-on workshop will cover:

1. Creating containerlab topologies, from CLI to GUI
You'll learn how to install and use containerlab, and how a containerlab topology file looks like. We present how containerlab works, the commands containerlab uses, the topology syntax, and also showcase some recent additions and changes made to containerlab in 2025. At the end of this section, you will have a ready-to use containerlab topology serving as a baseline for the next sections.

For veteran containerlab users, we provide a prepared topology that allows you to skip to the next section.

2. Sending and observing traffic in your virtual datacenter
In order to collect meaningful telemetry data, we should have some client traffic going across our topology. Hence, clients are added to the topology and test traffic is sent between the nodes. As part of this section, we also configure Edgeshark to allow us to perform remote packet captures from the containerlab host, and learn how to use the VS Code extension to capture live traffic and simulate link impairments.

3. Setting up a modern open-source telemetry stack
Having a virtual network is one thing, but most networks come with supporting infrastructure. We can leverage the Linux container ecosystem to easily add components of a network telemetry stack to our containerlab topology, which allows us to collect, store and visualize telemetry data from the network elements. We use gNMIc, Prometheus and Grafana to create a streaming telemetry dashboard that allows to monitor our datacenter.

4. Giving a Kubernetes-based network automation and telemetry solution a spin
Kubernetes is the de-facto industry standard container orchestration system, used worldwide from small scale to hyperscale environments. This robust system is not only useful for container orchestration, but for network management and orchestration as well, as we demonstrate this during this section.

You will use a Kubernetes-based network orchestrator to manage the configuration of the virtual datacenter and to collect telemetry from it. This section requires no prior Kubernetes experience, the whole interaction can be done through a UI or API.

A workshop for enterprise administrators who want to implement IPv6 in their companies. You will get a good idea where to start your journey to IPv6, who to take with you and which path to take. The workshop will be interactive and you should bring a laptop or tablet for getting the most out of this learning experience. After two hours you are ready to start your IPv6 project.

The network engineering industry is rich with technical talent but remains surprisingly underrepresented in the world of product-driven startups. In this workshop, Thomas Weible (CTO and Co-Founder, FLEXOPTIX) and Moritz Frenzel (CEO and Co-Founder, EdgeOps) share their entrepreneurial journeys, each shaped by a deep technical background and a commitment to building products instead of pursuing the traditional consulting route.

With FLEXOPTIX drawing on over 15 years of experience in building and growing a sustainable product company, and EdgeOps bringing the perspective of a fresh startup less than a year into its journey, the session offers both long-term insight and real-time relevance. Thomas and Moritz will each present a focused 15-minute talk covering their paths, followed by an open and interactive 90-minute discussion.

This workshop aims to inspire and equip engineers, founders, and future entrepreneurs with the confidence and perspective to transition from services to products, shifting from billing hours to building something that lasts, while also fostering connections between existing and aspiring founders.

I would like to start by talking about the things everybody assumes you already know about SSH. This is aimed at giving you the essentials of using SSH, with the focus on using it for work. The workshop covers topics like pub/privkey handling, key-based (passwordless) authentication and keeping your keys secure. The goal for this first part is to hopefully give you a foundational understanding of how to start working (and what not to do) with SSH and SSH keys.

Once we get done with the basics, we can start talking about useful things you can do with ssh beyond the basics. Covering topics like port forwarding, proxy jump, SSH certificates, control channel reuse, properly using ssh_config etc

The goal is for you to walk out of this workshop with a good understanding of how to use SSH efficiently to help you to focus on the thing you're actually working on.