Linux

I’m not a programmer, and I’m not trying to be one. But the development of new AI models has let me learn concepts that were once too complicated for me to get on my own. As you know, I use Linux a lot — but I still wanted to properly upskill in the command line. So instead of just following a document and re-typing commands in another terminal window, I thought: why not get Claude to build me an interactive game — a Linux CLI practice terminal — that actually lets me learn and memorise the commands? ...

A while back I hardened this Debian VM by hand — patched it, cut the attack surface, put a default-deny host firewall in front of it, sandboxed the custom services. I audited my own box and fixed the drift I found. The problem with auditing your own box is that you grade your own homework. You check the things you already think to check. So this time I handed the job to something that has no idea what I meant to do and only reports what’s actually there: Lynis, the system-auditing tool from CISOfy. It ran 274 tests and gave the VM a hardening index of 68 / 100. ...

My Debian automation VM already sits behind a pfSense firewall with egress containment — it can reach the internet but not my home network. So why harden the VM itself? Because “behind a firewall” is doing less work than it sounds. Two paths reach into the VM without ever crossing pfSense, and an honest audit of my own box turned up drift I didn’t expect. This is the write-up: what the audit found, what I changed, and the systemd sandbox mistake that quietly broke a service. ...