IPv4 Address Examples and Format

An IPv4 address has four decimal numbers separated by dots. Each number is between 0 and 255; the address contains 32 bits.

Examples at a glance

Your device and local network

Localhost: 127.0.0.1
Loops back to your own device.
Private router example: 192.168.1.1
Often used by home routers; the actual address varies.
Private network example: 10.0.0.1
Another address used inside private networks.

Public DNS services

Google Public DNS: 8.8.8.8
Google also provides 8.8.4.4.
Cloudflare DNS: 1.1.1.1
Cloudflare also provides 1.0.0.1.

Format and practice

General format: x.x.x.x
Four numbers from 0 to 255. The x characters are placeholders.
Documentation example: 192.0.2.10
Reserved for examples, rather than a live service.
Invalid example: 256.168.1.10
256 exceeds the limit of 255.

Read an IPv4 address

In 192.0.2.10, the four octets are 192, 0, 2 and 10. These documentation blocks are for examples, not public services to contact.

Valid and invalid spelling

256.1.2.3 is invalid because 256 exceeds the octet limit. 192.0.2 has too few octets. Our validator rejects leading zeros such as 192.000.2.10, and does not accept legacy integer or hexadecimal forms.

An address is not a subnet

192.0.2.10 identifies an address; 192.0.2.0/24 describes a prefix. A port such as :443 belongs to an endpoint, not the bare IPv4 literal.