IP Addresses (IPv4 Basics)

Give each host an address

An IP address identifies a host (or a network interface) so packets can be delivered. IPv4 is still the form you see most often on home networks.

Read the dotted format

An IPv4 address has four numbers from 0 to 255, separated by dots—for example 192.168.1.24. People also write a prefix length such as /24 to show how much of the address is the network part.

192.168.1.24/24

Separate host from network

Routers use the network portion to decide where to send traffic next. Hosts on the same local network share a network prefix and usually talk without leaving the LAN.

Expect more than one address

A laptop can have a private address on Wi-Fi, another on Ethernet, and a temporary address when it joins a guest network. Servers on the public internet use carefully assigned public addresses.