Notes from the network

Troubleshooting Diagnose a slow or overloaded VPS The site is up but everything is slow, and the usage graph only says "busy". Four commands tell you whether the server is short of CPU, memory, or disk, and which process is responsible. Sep 23, 2026 · 8 min read Tutorials Add swap to your VPS Your VPS ships with no swap, so when memory runs out the kernel kills a process and moves on. Here is how to spot that, add a swap file, and know when swap is the wrong fix. Sep 14, 2026 · 9 min read Tutorials Write cron jobs that do not fail silently Cron emails you when a job produces output. On a VPS with no mail server that email goes nowhere, so a broken job looks exactly like a working one. Jul 31, 2026 · 10 min read Tutorials Use SSH keys properly on your VPS Paste a public key on the order form and your server boots with it already installed. The root password still arrives by email, so here is how to finish the job. Jul 29, 2026 · 15 min read Tutorials Run several apps behind one Nginx reverse proxy One VPS, one public IP, several apps on local ports. How to give each app its own hostname and share one set of proxy headers between them. Jul 28, 2026 · 12 min read Tutorials Back up your VPS off server with restic How to put an encrypted restic repository on another machine, run it nightly from a systemd timer, and check that a restore actually works. Jul 27, 2026 · 17 min read Tutorials Set up fail2ban properly on your VPS Installing fail2ban takes one command. Making it actually ban anything takes a few more, starting with checking which log the sshd jail reads. Jul 23, 2026 · 10 min read Tutorials Install Mail-in-a-Box on a VPS One command turns a fresh Ubuntu server into a complete mail system with webmail, calendars, contacts, and its own DNS. It also takes over the whole machine. Jul 19, 2026 · 6 min read Tutorials Install docker-mailserver on a VPS A mail server with no web interface and no database, configured entirely from files and a setup command. The lightest of the container options. Jul 18, 2026 · 7 min read