Troubleshooting

A practical guide to the docker exec command, covering background execution, environment variables, interactive sessions, and working directory control. Includes real-world examples to help you get the most out of running commands inside containers.

A guide to inspecting SSL/TLS handshakes in Java applications when built-in debugging is unavailable. Includes a lightweight TLS client tool for testing certificate and handshake issues.

A walkthrough of using udevadm to diagnose and inspect udev rule application on a /dev/null device node. Covers the test command syntax and interprets the output for troubleshooting permission issues.

A deep dive into how the Linux kernel receives network packets, covering the full path from NIC hardware through NAPI, softirqs, GRO, RPS, and protocol layers. Includes practical monitoring commands and tuning knobs for each stage.

A practical walkthrough of how Linux allocates and manages RX/TX ring buffers for network interfaces, covering DMA, softirq processing, and tuning knobs like netdev_budget.

A practical breakdown of the most common misconceptions about /dev/urandom and /dev/random on Linux, explaining why /dev/urandom is the correct choice for cryptographic randomness and why blocking on low entropy is a usability problem, not a security one.