IPv4 and IPv6

Overview

This lecture covers the basics of IPv4 and IPv6 addressing, key configuration parameters for network devices, and the importance of DNS in modern networking.

IPv4 Addresses

• IPv4 is the main protocol used for network communication today.
• An IPv4 address consists of four decimal numbers separated by periods (e.g., 192.168.1.131).
• Each part (octet) of the IPv4 address is 8 bits, for a total of 32 bits.
• The maximum value of an octet is 255, since 8 bits can represent values from 0 to 255.
• IPv4 addresses are usually displayed in decimal, but can be represented in binary.

IPv6 Addresses

• IPv6 was created because IPv4 could not provide enough addresses for the growing internet.
• An IPv6 address is 128 bits long and consists of eight groups of four hexadecimal digits.
• Each group in IPv6 represents 16 bits (2 bytes or 2 octets).
• IPv6 addresses are written in hexadecimal and separated by colons (e.g., fe80::5d18:652:cffd:8f52).
• IPv6 commonly uses a 64-bit subnet mask, dividing the address into network and host portions.
• The vast address space allows for unique addresses for nearly any device.

IP Configuration Parameters

• Devices need a unique IP address and subnet mask to communicate on a network.
• A subnet mask (e.g., 255.255.255.0) defines the network and host portions of the address.
• The default gateway is the router’s IP address that allows communication outside the local subnet.
• Both the IP address and subnet mask must be assigned together for proper configuration.

Domain Name System (DNS)

• DNS translates domain names (e.g., www.google.com) into IP addresses.
• Network devices rely on DNS to convert human-friendly names to numeric addresses.
• DNS server addresses are configured in the operating system’s IP settings.
• It is common to configure multiple DNS servers for redundancy (e.g., 8.8.8.8 and 8.8.4.4).

Key Terms & Definitions

• IPv4 — A 32-bit address protocol split into four octets, used widely for network communication.
• IPv6 — A 128-bit address protocol using hexadecimal, designed to replace IPv4.
• Octet — An 8-bit segment of an IP address.
• Subnet Mask — A value that divides an IP address into network and host components.
• Default Gateway — The router’s address allowing devices to access networks outside their local subnet.
• DNS (Domain Name System) — A service that translates domain names into IP addresses.

Action Items / Next Steps

• Practice identifying and converting between decimal, binary, and hexadecimal IP address formats.
• Review how to configure IP addresses, subnet masks, default gateways, and DNS servers on your operating system.