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Networking

Networking is the discipline of connecting computers and devices to share resources, exchange data, and enable communication. It encompasses the physical infrastructure, protocols, services, and security mechanisms that make the internet and local networks function.

OSI Model

The Open Systems Interconnection (OSI) model provides a seven-layer framework for understanding network communication, from physical transmission to application-level protocols.

See Article - OSI network model for a detailed breakdown of the OSI layers.

Interfaces and Addressing

Network interfaces are the points of connection between a host and a network. Linux provides tools for configuring physical and virtual interfaces, bridges, bonds, and VLANs.

IP addresses identify hosts on a network. IPv4 uses 32-bit addresses; IPv6 uses 128-bit addresses with improved features like autoconfiguration and larger address space.

See Article - Interfaces/bridge, IPv4/IPv6 addressing for interface configuration and IP addressing.

Core Protocols

Networking relies on protocols that define how data is formatted, addressed, transmitted, and received.

  • ARP: Maps IP addresses to MAC addresses on local networks.
  • ICMP: Diagnostic and error reporting (ping, traceroute).
  • TCP: Reliable, connection-oriented transport.
  • UDP: Fast, connectionless transport for real-time applications.

See Article - Main protocols: ARP, ICMP, UDP, TCP for details on ARP, ICMP, UDP, and TCP.

DNS

The Domain Name System translates human-readable hostnames into IP addresses. It is a hierarchical, distributed database that underpins almost all internet communication.

See Article - DNS for DNS fundamentals, and Article - DNS - dnsmasq and Article - DNS - coredns for DNS server implementations.

Routing

Routing determines the path packets take across networks. Routers use routing tables and protocols to forward packets toward their destinations.

See Article - Routing for static and dynamic routing.

Firewalls and NAT

Firewalls filter network traffic based on rules. NAT (Network Address Translation) allows multiple devices to share a single public IP address.

See Article - netfilter, firewall, conntrack, masquerade for iptables, nftables, connection tracking, and masquerade.

VPN

Virtual Private Networks create encrypted tunnels over untrusted networks, extending private networks securely across the internet.

See Article - VPN for VPN technologies including IPsec, OpenVPN, and WireGuard.

Wireless (WLAN)

Wi-Fi networks use the IEEE 802.11 standard for wireless communication. Linux provides tools for configuring wireless interfaces, access points, and security.

See Article - WLAN for WLAN configuration and security.

DHCP

The Dynamic Host Configuration Protocol automatically assigns IP addresses and network configuration to devices.

See Article - DHCP for DHCP server and client configuration.

VLANs

Virtual LANs segment a physical network into isolated logical networks, improving security and broadcast control.

See Article - VLAN for VLAN configuration on Linux.

Peer-to-Peer

Peer-to-peer networking enables decentralised communication and resource sharing without centralised servers.

See Article - peer to peer for P2P architectures and technologies.