Category: worth reading

Another must-explore gem by Julia Evans: Popular git config options.

Side note: I keep collecting links to insightful Git articles in the Git and GitHub section of the Network Automation Tools webinar.

I ran the first webinar as an independent author almost exactly fourteen years ago¹, with the first ticket sold just before New Year’s Eve. I kept focusing on individual webinars until someone asked me, “Would it be possible to buy access to everything you did?” His question effectively created the ipSpace.net subscription, with the first one sold in late 2010 (I still have the email that triggered the whole process).

After procrastinating for months, I finally spent a few days cleaning up and organizing OSPF blog posts (it turns out I wrote almost 100 blog posts on the topic in the 18 years of blogging).

Eric Hoel published a spot-on analysis of AI disruptiveness, including this gem:

The easier it is to train an AI to do something, the less economically valuable that thing is. After all, the huge supply of the thing is how the AI got so good in the first place.

TL&DR: AI can easily disrupt things that are easy to generate and thus have little value. Seeing investors trying to recoup the billions pouring into the latest fad will be fun.

Gerben Wierda published another AI-buster article describing what exactly “state-of-the-art” means in AI benchmarks.

Hint: you give an AI model 32 step-by-step examples before asking a question, and it still gets it wrong 10% of the time.

I always said that the Trivia Pursuit certification tests (or job interviews) are nonsense and that one should focus on fundamentals.

In a recent blog post, Daniel Dib described a fantastic scenario: using a simple “why can’t I connect to a web site” question, explore everything from ARP/ND to DNS and TLS.

Obviously, you’ll never see anything that sane in a certification test. An interactive interview doesn’t scale (beyond CCDE), and using humans (and common sense judgment) creates potential legal liabilities (there were rumors that had been one of the reasons a talk with a proctor who could flunk you was dropped from the CCIE test).

Did you find the Network Automation with GitHub Actions blog post interesting? Here are some more GitHub Self-Hosted Runner goodies from Julio Perez: Network CI and Open Source – Welcome to the World of Tomorrow. Enjoy!

What happens when you let a bunch of people work on different aspects of a solution without them ever talking to each other? You get DNS over IPv6. As nicely explained by Geoff Huston, this is just one of the bad things that could happen:

Around 30 years after we got the first website, the powers that be realized it might make sense to put this is how you access a web server information (including its IPv4 and IPv6 address, and HTTP(S) support information) directly into DNS, using HTTPS Resource Records. It took us long enough 🤷‍♂️

George Davitiani put together a lovely proof-of-concept using GitHub actions to deploy modified configurations to network devices. Even better, he documented the whole setup, and the way to reproduce it. I’m positive you’ll find a few ideas browsing through what he did.

Daniel Teycheney decided not to renew his CCNP status and used this opportunity to publish his thoughts on IT certifications. Not surprisingly, I agree with most of the things he said, but I never put it in writing so succinctly.

Red Pill Warning: Reading his blog post might damage your rosy view of the networking industry. You’ve been warned ;)

Cloudflare experienced a significant outage in early November 2023 and published a detailed post-mortem report. You should read the whole report; here are my CliffsNotes:

• Regardless of how much redundancy you have, sometimes all systems will fail at once. Having redundant systems decreases the probability of total failure but does not reduce it to zero.
• As your systems grow, they gather hidden- and circular dependencies.
• You won’t uncover those dependencies unless you run a full-blown disaster recovery test (not a fake one)
• If you don’t test your disaster recovery plan, it probably won’t work when needed.

Also (unrelated to Cloudflare outage):

Julia Evans wrote another must-read article (if you’re using Git): git rebase: what can go wrong?

I often use git rebase to clean up the commit history of a branch I want to merge into a main branch or to prepare a feature branch for a pull request. I don’t want to run it unattended – I’m always using the interactive option – but even then, I might get into tight spots where I can only hope the results will turn out to be what I expect them to be. Always have a backup – be it another branch or a copy of the branch you’re working on in a remote repository.

Julia Evans wrote another great article explaining confusing git terminology. Definitely worth reading if you want to move past simple recipes or reminiscing about old days.

Almost exactly a decade ago I wrote about a paper describing how IBGP migrations can cause forwarding loops and how one could reorder BGP reconfiguration steps to avoid them.

One of the paper’s authors was Laurent Vanbever who moved to ETH Zurich in the meantime where his group keeps producing great work, including the Chameleon tool (code on GitHub) that can tame transient loops while reconfiguring BGP. Definitely something worth looking at if you’re running a large BGP network.