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Post-quantum key exchange

Posted on 2026-03-172026-03-18 By rolfje No Comments on Post-quantum key exchange

If you see this warning when connecting to a server through ssh:

 ** WARNING: connection is not using a post-quantum key exchange algorithm. ** This session may be vulnerable to "store now, decrypt later" attacks. ** The server may need to be upgraded. See https://openssh.com/pq.html 

Then follow michabbb’s guide on how to enable post-quantum key exchange in ssh. Don’t worry, you don’t have to generate new keys. Please please do not disable the warnings, Solution 1 is NOT a solution. Do the right thing.

On your (MacOS) client machine (your local laptop) you need to tell your client to prefer post-quantum algorithms. Edit ~/.ssh/config and make sure your Host entry contains a KexAlgorithms line like this:

 Host * KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org 

On a (MacOS) server you need to tell the sshd deamon to prefer post-quantum algorithms. To help you quickly do this:

 sudo tee /etc/ssh/sshd_config.d/post-quantum.conf >/dev/null <<'EOF' # Enable post-quantum key exchange algorithms KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256 EOF sudo launchctl unload /System/Library/LaunchDaemons/ssh.plist sudo launchctl load -w /System/Library/LaunchDaemons/ssh.plist 

Then validate that it worked on your next ssh session. If not, check that both machines (client and server) contain these fixes and are up-to-date. Read michabbb’s article for more tips and a better explanation.

Stay safe!

Apple, Software

Addictive Intelligence

Posted on 2026-03-162026-03-17 By rolfje No Comments on Addictive Intelligence

Developer jugglingThe past months were hectic. Artificial Intelligence has changed my daily work faster than I expected. In just a few weeks, it went from a fun experiment to something that reshaped how I “write” software, how I think, and even how tired my brain feels at the end of the day. It brings cool new possibilities, but also new challenges. I thought I’d write some of it down for future reference.

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Software

How to tail a json log file

Posted on 2026-02-182026-02-19 By rolfje No Comments on How to tail a json log file

Robot-tieMany applications nowadays output json formatted log files so that they can be scraped by the newest hippest monitoring cluster (think of Splunk, Elastic Filebeat, etc). That is of course very nice and I applaud that kind of observability, but sometimes you are just on the machine fighting with a service that does not want to start, or you just want to monitor it a bit more realtime, or you just are not the browser type. Luckily there is a realatively easy trick to this.

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Software

Are you de-skilling?

Posted on 2026-02-052026-02-06 By rolfje 2 Comments on Are you de-skilling?

Coding panicThis week a colleage of mine shared an interesting video describing AI (mainly Suno) as problematic to the musical industry in the sense that musicians will become less and less skilled in making truly original music. It coins the term “de-skilling”, which perfectly captures something I also see in the software development area, even though it is beautifully hidden by the “impressive results”.

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Software

European alternatives to AWS/Azure/GoogleCloud

Posted on 2026-01-272026-01-27 By rolfje 1 Comment on European alternatives to AWS/Azure/GoogleCloud

Icon depicting European Cloud ProvidersThis article lists a rough feature comparison between currently available European cloud providers and their American counterparts. European cloud is available and abundant. Stackit, OVHcloud, Scaleway, IONOS, Exoscale, Upcloud are all parties you should have on your radar when building critical infrastructure for European clients. The US is proving to be less and less reliable as an IT partner. You’ve got to move.

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Software

GT7 Safety Ratings Broken

Posted on 2026-01-212026-02-02 By rolfje No Comments on GT7 Safety Ratings Broken

I regularly play Gran Turismo 7 on my playstation 5. Fanatec Direct Drive steering wheel, seat, pedals, the works. I even have a pit crew telling me when my tyres are warm or cold, and which laps I need to pit in by using EzioDash Pro. I put great effort in keeping my SR (Safety Rating) as high as possible, hoping that I get placed in lobbies where people behave. I very regularly get the “Clean Race” bonus, and my SR is maxed out. Yet still I get into lobbies with dimwits like NicoTabe or JabCrash. Last week I noticed that these dirty drivers actually get increased safety ratings. This video clearly shows the problem:

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Racing

Add iptables to your node-exporter metrics

Posted on 2025-12-012025-12-11 By rolfje No Comments on Add iptables to your node-exporter metrics

This time quick and simple trick to make your node_exporter report on the number of blocked and allowed packets by iptables. It involves a tiny script, and a small configuration change to the node_exporter. Here we go:

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Software

Finding HomeAssistant Entities in Prometheus

Posted on 2025-11-09 By rolfje No Comments on Finding HomeAssistant Entities in Prometheus

Juggling entities in HomeAssistantWhen you install the prometheus addon in HomeAssistant, it can be strange to see that the metrics do not show up in your Grafana dashboard. That is because the entity names are part of the labels, not of the metric name.

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Uncategorized

Querying Classicpress database for page hits

Posted on 2025-11-012025-10-21 By rolfje No Comments on Querying Classicpress database for page hits

Now that I am running classicpress, I miss the statistics that I received at wordpress.org. I don’t want to install third party cookies or other adware stuff, so I was looking to see how to solve that completely locally. Here’s how I got it working, withouts ads, all local, for free.

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Software, Uncategorized

Gardena Sileno verbindingsprobleem opgelost

Posted on 2025-10-202025-10-21 By rolfje No Comments on Gardena Sileno verbindingsprobleem opgelost

In de zomer groeit gras als een malle. Eigenlijk zou je 2 a 3x per week moeten maaien als je het mooi wil houden, en met een kooimaaier wordt dat al snel klusje dat je uitstelt of overslaat. Dus kochten we een prachtige robotgrasmaaier van Gardena: De Sileno City met LONA technologie (daarmee maakt hij een mooie kaart van je tuin die je ziet in de app op je telefoon).

Bij het installeren meldde hij dat het lussignaal en de geleidingsdraad niet waren gevonden, ook al stond hij in de lader en was alles correct aangesloten (groen lampje in de lader). In deze post leg ik uit waar dat door (kan) komen en welke oplossing NIET in hoofdstuk 6 “Probleemoplossingen” in het boekje staat.

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