Networking
DNS, IP addresses, IPv6, firewalls, latency and DDoS protection explained for your servers and sites.
- DNS basics for a new domain DNS decides where your domain's website and email live. The parts in plain language: registrar and nameservers, the records you will use and how changes spread. Beginner 15 min
- Point a domain to your server Two ways to send your domain to your server: edit the records where your DNS lives, or move the whole zone with new nameservers. Pick one and verify it. Beginner 10 min
- Reverse DNS (PTR) for your server's IP address A PTR record maps your IP address back to a name. Mail servers check it, so set it to a host name that points back to the same address. Beginner 8 min
- Configure and test IPv6 on your server If your service has IPv6 addresses, configure one on the server, test it from outside, open the firewall for IPv6 and add an AAAA record. Intermediate 15 min
- Set up a firewall with UFW on Ubuntu and Debian UFW is the simplest way to run a deny-by-default firewall on Ubuntu and Debian. Set it up in the right order so you never lock yourself out. Beginner 15 min
- Build a server firewall with nftables nftables is the Linux firewall framework that Debian uses by default. One readable file describes the whole firewall for IPv4 and IPv6. Intermediate 20 min
- Windows Defender Firewall rules with PowerShell Windows Server's built-in firewall is all most servers need. These PowerShell commands cover the rules you will use, and how to test them safely. Intermediate 15 min
- Ports and port forwarding on a server, explained A port is reachable when a service listens on the right address and the firewall allows it. Check both, test from outside, and use tunnels instead of opening admin ports. Intermediate 15 min
- Put Cloudflare in front of your website Cloudflare's proxy caches your site, filters attacks and hides your server's address. Set it up correctly so HTTPS, logs and your firewall keep working. Intermediate 25 min