Topic
#systems
4 posts
- Testing the eMudhra CA fix: four shortcuts that don't work When a certificate authority is distrusted, the advice is to upgrade certifi, upgrade pip and rebuild. I followed that advice in the official Docker images, then asked each client to connect to a site signed with a cracked key. Four fixes that looked right did nothing. The only proof is your client refusing a bad certificate. 6 min read #systems#security#tls
- What happens when you press 5 on a phone call A key press is two sine waves. On a modern VoIP call it is usually not sound at all, but a small packet that says which key and for how long. A walk from the 1960 Bell Labs design to RFC 4733, with the codec test that drops digits. 9 min read #systems#telephony#voip
- A symlink is just a path, and that explains everything Why upgrading Python leaves two versions behind, why your venv breaks, why ln -sfn is safe on Linux but not on a Mac, and twelve more things a symlink can do to you. Every claim comes with output you can reproduce. 7 min read #systems#linux#filesystems
- Our computers don't really know what time it is A trip down the rabbit hole of quartz crystals, cesium atoms, GPS, NTP, and PTP, after chrony told me my clock was running slow. 2 min read #systems#time#ntp