Ssh Hardening

This hardens SSH on your VPS by creating a non-root sudo user, setting up key-based authentication, and disabling password login and root access. You'd use it when spinning up a new server or fixing an existing one that's still using passwords and allowing root login. The documentation is thorough about the "keep a session open while testing" warnings, which matters because it's easy to lock yourself out if you disable password auth before confirming your SSH keys work. Covers Ubuntu, Debian, CentOS, and RHEL with step-by-step commands for the full workflow from ssh-keygen through sshd_config changes. The troubleshooting section assumes you've already made the mistake, which is realistic.