~/tutorials $
Linux server tutorials
Step-by-step tutorials for a Linux server: VPNs, web servers, databases, containers, security and backups. Each one names the distributions it was tested on.
11 of 45 tutorials in Security
How to check open ports on Linux with ss and nmap
List the ports your server listens on with ss, find which program owns each one, then scan the server from outside with nmap to see what the internet can reach.
How to configure firewalld on AlmaLinux and Rocky Linux
Turn on firewalld, open services and ports for good, limit SSH to your own addresses with a zone, and use rich rules, without locking yourself out.
How to create a sudo user and disable root login on Ubuntu and Debian
Add a normal user with sudo rights on Ubuntu or Debian, give it your SSH key, then stop root logging in over SSH without locking yourself out.
How to create a sudo user on AlmaLinux and Rocky Linux
Add a user to the wheel group on AlmaLinux or Rocky Linux, give it your SSH key with the right SELinux labels, and turn off root logins over SSH.
How to get a Let's Encrypt wildcard certificate with the DNS challenge
Get a free *.example.com certificate from Let's Encrypt with certbot or acme.sh and your DNS provider's API, renew it automatically and reload your web server.
How to install and secure Redis on Ubuntu 24.04
Install Redis on Ubuntu 24.04, keep it on localhost, replace the open default user with ACL users, block dangerous commands and cap its memory.
How to install CrowdSec on Ubuntu and Debian
Install the CrowdSec engine and its nftables firewall bouncer, watch SSH and nginx logs, allowlist your own addresses, and see what it blocks.
How to set up a WireGuard VPN server on AlmaLinux and Rocky Linux
Install WireGuard on AlmaLinux or Rocky Linux, write wg0.conf, route clients through the server with firewalld masquerading, and connect your devices.
How to set up a WireGuard VPN server on Ubuntu 24.04
Install WireGuard on Ubuntu 24.04, write the server config, route clients' traffic through it and connect a laptop and a phone.
Manage VPSNine servers with Ansible
Build an Ansible inventory from the VPSNine API, grouped by tag, plan and image, and run a playbook that patches servers and locks SSH to keys.
Self-host Vaultwarden safely with Docker and HTTPS
Run Vaultwarden, the Bitwarden-compatible password server, in Docker behind Caddy with HTTPS, sign-ups closed, a hashed admin token and backups you can restore.