Networking

Covers enough networking to configure, secure, and debug a typical Linux host - not a general networking course.

• DNS and Resolution

  How a Linux machine turns a hostname like example.com into an IP address before it can connect to anything - the resolution chain, and the tools for testing it directly.

• Firewalls: iptables and nftables

  iptables and nftables are two generations of the same kernel packet-filtering framework (netfilter) - most distros put a friendlier frontend like ufw or firewalld in front of whichever one they use.

• Networking Basics

  The core concepts behind a Linux machine's network configuration - interfaces, IP addresses, and routing - and the modern `ip` command for inspecting all three.

• SSH

  SSH (Secure Shell) is the standard way to log into and run commands on a remote Linux machine over an encrypted connection - this covers the client side, config file, and basic server settings.

• Troubleshooting Connectivity

  A layer-by-layer process for diagnosing "the network doesn't work" - checking the interface, address, routing, DNS, and firewall in order rather than guessing.