Firewalls
DNS, IP addresses, IPv6, firewalls, latency and DDoS protection explained for your servers and sites.
- 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