---
title: "IP Address"
description: "An IP address is a unique number that identifies a device on a network using the Internet Protocol. Learn how it works and how IPv4 differs from IPv6."
url: "https://nodea.io/en/glossary/ip-address"
lang: "en"
updated: "2026-07-13"
---

# IP Address

> An IP address is a unique number that identifies a device on a computer network and lets data packets be routed to it.

An **IP address** (Internet Protocol address) is a unique number that identifies a device on a network that runs the Internet Protocol. It plays a dual role: it says which device is involved (identification) and where it sits in the network (addressing), so that data packets reach exactly where they should.

## How an IP address works

When a browser connects to a website, the data is split into packets, and each one carries a sender and a destination address. Routers along the way read the destination IP address and pass the packet ever closer to its target — much like a postal service uses a postcode and address. Two versions of the protocol exist: [IPv4](https://nodea.io/en/glossary/ipv4-address), written as four numbers (e.g. 192.0.2.10), and the newer [IPv6](https://nodea.io/en/glossary/ipv6-address), which solves the shortage of available addresses.

Because people do not memorize strings of digits, in practice we use domain names. The [DNS](https://nodea.io/en/glossary/dns) system translates a readable name (e.g. nodea.pl) into its matching IP address — stored in an A record for IPv4 or an AAAA record for IPv6.

## IP addresses in practice

Every web server, mail server, or networked device has an IP address assigned to it. In hosting, the server's IP address decides where traffic is sent once a domain resolves; when you move a site to a new VPS, it is this address that changes in the DNS records. IP addresses are also used for firewall filtering, geolocation, rate limiting, and connection diagnostics with tools such as **ping** and **traceroute**. In shared environments many sites may use one address (distinguished by the Host header), whereas services that need full control, such as a dedicated mail server or certain certificates, rely on a dedicated IP address bound to a single server.

### Is an IP address fixed or dynamic?

An IP address can be static (permanently assigned, for example to a server) or dynamic — handed to a device for the duration of a session by the internet provider's DHCP server. Hosting servers typically use static addresses.

### What is the difference between a public and a private IP address?

A public address is routable across the internet and globally unique, while a private address (such as 192.168.x.x) works only inside a local network. Devices on a private network reach the internet through NAT.

## Related

- [IPv4 Address](https://nodea.io/en/glossary/ipv4-address)
- [IPv6 Address](https://nodea.io/en/glossary/ipv6-address)
- [DNS](https://nodea.io/en/glossary/dns)
- [DNS Server](https://nodea.io/en/glossary/dns-server)
- [A record](https://nodea.io/en/glossary/a-record)

---

Languages: [pl](https://nodea.pl/pl/slownik-pojec/adres-ip.md)  
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