Linux, servers and SSH
The subject here is running a Linux server of your own: access over SSH, hardening, services and backups. Each guide explains the steps, and also what the commands used actually do.
UFW firewall on Ubuntu: a safe setup over SSH, step by step
Set up a UFW firewall on Ubuntu 24.04 LTS: deny incoming by default, allow SSH first, rate-limit logins, handle IPv6 and avoid the Docker bypass.
SSH config file: set up ~/.ssh/config once and connect to every server by name
SSH config file explained: Host blocks, IdentityFile, ProxyJump, keepalives, connection sharing, which value wins and how to debug with ssh -G and ssh -v.