Linux server tutorials

6 of 45 tutorials in Networking and VPN

1. 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.

   beginner · 10 min · Ubuntu 24.04 LTS

2. 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.

   beginner · 20 min · AlmaLinux 10, Rocky Linux 9

3. How to point a domain at your VPS (A and AAAA records)

   Point your domain at your server with A and AAAA records, add www, pick a sensible TTL, and check with dig that the change has really taken effect.

   beginner · 15 min · Debian 13 Stable

4. How to send email from a VPS through an SMTP relay

   Send your server's mail (alerts, cron output, app email) through an SMTP relay on port 587 with Postfix, so it's delivered without running a full mail server.

   intermediate · 20 min · Debian 13 Stable

5. 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.

   intermediate · 30 min · AlmaLinux 10, Rocky Linux 9

6. 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.

   intermediate · 30 min · Ubuntu 24.04 LTS