# Overview

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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.