Cisco VRRPv3 IPv6 Configuration Sucks

I spent way too much time ironing out the VRRPv3 quirks on the dozen (or so) platforms supported by netlab. This is the second blog post describing some of the ridiculous stuff I had to deal with.

This is how you configure the basic VRRPv3 parameters for IPv4 on a Cisco IOS/XE device:

VRRPv3 IPv4 configuration on Cisco IOS
interface GigabitEthernet0/1
  vrrp 217 address-family ipv4
    address 172.16.33.42

You would expect something similar for IPv6, right? You’d be right if you were working with Arista EOS:

Read more …

From Python to Go 012. Processing User Input From CLI Arguments And Standard Input.

Hello my friend,

Whenever we develop any network and IT infrastructure automation applications, we need to have some options to provide user input. In previous blog posts in these series we already covered how to provide user input via environment variables and files. Whilst these two approaches can cover majority of your use cases, especially if you develop containerized applications running in autonomy, there are still two options we would like to talk today about.

Why To Bother Learning Automation?

For many years I was doing network design and operation without automating it (or at least without structured approach to automate it). And there are still loads of such job positions out there. And I see it based on the audience of my blog: majority of people here for networking knowledge, much less are for automation topics. From pure pragmatic standpoint of writing popular blogs, I should stick to network technologies, especially something fancy as SD-WAN and others. However, from the direction of the technologies development, I see that value (including jobs) comes from intersection of domains: networking, compute, storage, software development, data bases, Kubernetes, observability, etc. I’m of a strong opinion that engineers these days must be aware of Continue reading

Palo Alto How to Configure SSL Decryption?

Palo Alto How to Configure SSL Decryption?

Most websites we access today use HTTPS, and to fully leverage a Next-Generation Firewall (NGFW) like Palo Alto, inspecting encrypted HTTPS sessions is crucial. Configuring SSL decryption isn't just a set-it-and-forget-it task. It requires careful consideration and ongoing improvements. In this blog post, we'll explore how to configure SSL decryption in Palo Alto firewalls and highlight some pitfalls to be aware of. So, let's get to it.

As always, if you find this post helpful, press the ‘clap’ button on the left. It means a lot to me and helps me know you enjoy this type of content.

Palo Alto How to Block Specific URLs?
In this blog post, we’ll explore how to block specific sites using a Palo Alto firewall. There are two ways to achieve this, and we’ll cover both options.
Palo Alto How to Configure SSL Decryption?PacketswitchSuresh Vina
Palo Alto How to Configure SSL Decryption?

SSL Decryption Considerations

As I mentioned earlier, configuring SSL decryption isn’t as simple as flipping a switch. Decryption allows your firewall to inspect the contents of encrypted sessions. Normally, HTTPS traffic is encrypted from your browser to the server, ensuring the sessions are private. However, with SSL decryption, the firewall acts as a man-in-the-middle, inspecting the traffic in plain text. It’s crucial Continue reading

Weekend Reads 012425


AI errors come at seemingly random times, without any clustering around particular topics. LLM mistakes tend to be more evenly distributed through the knowledge space. A model might be equally likely to make a mistake on a calculus question as it is to propose that cabbages eat goats.


In this post, we start by explaining the configuration of our switching infrastructure using common IETF protocols to implement redundancy, full usage of resources, and seamless adaptivity in case of failures or maintenance. We then continue presenting the configuration of our route servers with a special focus on isolating different LANs and dynamically excluding invalid routes.


LLMs are undeniably astonishingly good at using the text they trained on (aided by human fine tuners) to generate convincing prose. But they are really bad at distinguishing between truth and falsehoods and responding to prompts that are unlike or even slightly different from what they trained on.


I wonder how many of you have noticed a subtle change in the way that you navigate the web? We’re in the midst of a transition to the zero click Internet, meaning users no longer have to click on links to reach web sites to find content.


Time Continue reading

Hedge 256: The Impact of Your First Language

Richard Wexelblat published an article in 1980 titled: “The consequences of one’s first programming language.” We’ve all seen C code written like Python, or Python code written like C, so it’s obvious a coder’s first language has a long lasting effect on their style. What about network engineers? Are there times and places where the first of anything a network engineers encounters has a long lasting impact on the way they think and work? In this roundtable, Tom, Eyvonne, and Russ consider different ways this might apply to network engineering.

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Use BGP Outbound Route Filters (ORF) for IP Prefixes

When a BGP router cannot fit the whole BGP table into its forwarding table (FIB), we often use inbound filters to limit the amount of information the device keeps in its BGP table. That’s usually a waste of resources:

  • The BGP neighbor has to send information about all prefixes in its BGP table
  • The device with an inbound filter wastes additional CPU cycles to drop many incoming updates.

Wouldn’t it be better for the device with an inbound filter to push that filter to its BGP neighbors?

Read more …

Sturgeon’s Law, VRRPv3 Edition

I just wasted several days trying to figure out how to make the dozen (or so) platforms for which we implemented VRRPv3 in netlab work together. This is the first in a series of blog posts describing the ridiculous stuff we discovered during that journey

The idea was pretty simple:

  • Create a lab with the tested device and a well-known probe connected to the same subnet.
  • Disable VRRP (or interface) on the probe and check IPv4 and IPv6 connectivity through the tested device (verifying it takes over ownership of VRRP MAC and IP addresses).
  • Reenable VRRP on the probe and change its VRRP priority several times to check the state transitions through INIT/BACKUP(lower priority)/MASTER(change in priority)/BACKUP(preempting after a change in priority).
Read more …

NAN083: Cox Gets Network Automation Right, and Proves It at DEF CON (Sponsored)

Today’s Network Automation Nerds episode discusses Cox Communications’ journey to getting network automation right. We also talk about how they used network automation to support operating the network at the DEF CON hacker convention. Our guests are David Ezell, Joshua Watkins and Eric Hansen from Cox Communications. We dive into initial steps and challenges in... Read more »

D2DO263: An Anthropologist’s Advice for Improving IT Cultures

It’s tempting to run IT organizations the same way we run infrastructure: as resource units to be applied to various jobs. But people aren’t infrastructure. They have opinions. They form teams. They operate on different incentives, which sometimes clash within an organization (i.e. sales vs. product managers, or infosec vs. everybody). Today’s guest, Lianne Potter,... Read more »

HLRS Takes First Steps To Exascale

The University of Stuttgart’s High Performance Computing Center (HLRS) in Germany tapped Hewlett Packard Enterprise back in December 2023 to build a prototype hybrid CPU-GPU supercomputer nicknamed “Hunter” to pave the way towards an exascale-class machine it is budgeting to have installed in 2027 called “Herder.” …

HLRS Takes First Steps To Exascale was written by Timothy Prickett Morgan at The Next Platform.

Running EVE-NG in Proxmox

Running EVE-NG in Proxmox

If you follow my blogs, you might know that I recently switched to Proxmox from VMware Workstation Pro for my home lab. I’ve already migrated most of my VMs, including Cisco CML, to Proxmox, and the last piece left was EVE-NG. In this blog post, we’ll go through the steps to install EVE-NG in Proxmox. Let’s get started!

As always, if you find this post helpful, press the ‘clap’ button on the left. It means a lot to me and helps me know you enjoy this type of content.

Running Cisco CML in Proxmox
In this blog post, we’ll go through how to install Cisco CML (specifically CML 2.8 Free Tier) on Proxmox.
Running EVE-NG in ProxmoxPacketswitchSuresh Vina
Running EVE-NG in Proxmox

Overview

EVE-NG doesn’t have official documentation for Proxmox, but it works perfectly fine, and I haven’t faced any issues so far. For this example, I’m using

  • Proxmox version 8.3.0
  • EVE-NG Community Edition 6.2.0

Most of the VM’s settings can be left at their default values, but there are a couple of changes I had to make. Before diving in, let's have a quick look at Nested Virtualization.

Nested Virtualization

Nested virtualization allows you to run virtual machines Continue reading

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