Overview

IP addresses allow machines to address each other across a network. IPv4 is still the most widely used version of the protocol, but the IPv4 address space is being consumed rapidly. IPv6 is the most recent version of the protocol, designed to solve the address space problem.

Terminology

IP Address

A unique identifier for a device on a network (e.g., 192.168.1.10 or 2001:db8::1)

IPv4

32-bit addressing (e.g., 192.0.2.1), widely used but running out of addresses

IPv6

128-bit addressing (e.g., 2001:db8::1), created to solve IPv4 exhaustion

Subnet

A segment of an IP network defined by a subnet mask or prefix (e.g., /24 for IPv4, /64 for IPv6)

Default Gateway

The router that forwards traffic to destinations outside the local network

Private IP

IPs used only inside local networks (e.g., 192.168.0.0/16 or fd00::/8)

Public IP

Globally routable addresses used on the Internet

NAT

Network Address Translation, allows many devices to share one public IPv4 address

Loopback Address

Refers to the local machine (127.0.0.1 for IPv4, ::1 for IPv6)

Broadcast

(IPv4 only) Sends traffic to all devices in a subnet (e.g., 192.168.1.255)

Features

You can selectively enable IPv6 on new or existing instances. Once enabled, an IPv6 will be automatically configured on the first interface of your instance, along with its public IPv4 address.