What is an IP address and what is it used for?

An IP address identifies a network interface for communication. IPv4 addresses are commonly written as four numbers separated by dots. IPv6 uses a different representation; not every IP address has the x.x.x.x form.

The original article compares an IP address to a person's identity-document number. That can help explain the idea of identification, but an IP address is not a permanent personal identity: it can change or be shared.

Devices that can use IP addresses

• Desktop computers and laptops.
• Network printers and cameras.
• Mobile phones and tablets.
• Game consoles.
• Wi-Fi-connected air conditioners and other connected equipment.

Local addresses

A device on a home or office network commonly has a private address used to communicate locally, for example with a printer or shared resource. An address alone does not grant access to those resources.

The original example 127.0.0.1 is a special case: it is a loopback address referring to the same computer, not a typical address for reaching another device on the LAN. IANA lists the loopback and private-use ranges in its IPv4 special-purpose registry.

Public addresses

The original article describes the common home-network arrangement in which devices behind one router share an outward-facing public IPv4 address. This is a useful example, not a rule covering every network: the address arrangement depends on the provider, configuration and IP version.

Web services can observe the source address of a connection and may use it for security or geographic statistics. That does not mean that every website uses it in the same way.

What an address does not reveal

IP geolocation is an estimate, not a way to pinpoint a person's home. MaxMind explains that its data cannot reliably identify a particular household, person or street address; VPNs and other network arrangements can further affect the result. See its geolocation accuracy guidance.

The original article also discusses identification in investigations. An IP address by itself is not proof of who used a device or their exact location. Provider records and other evidence are separate from a public IP lookup.

This edition distinguishes IPv4 from IPv6, explains the loopback example and qualifies the original identity and location claims. It does not provide a method for locating a person.