# IP address

> The number that identifies a device on a network, like a postal address.

- Level: Basic
- Topics: Networks
- URL: https://tidbit.legios.com.ar/ip-address/
- In Spanish: [Dirección IP](https://tidbit.legios.com.ar/es/ip-address/)

An **IP address** is a number that identifies a device on a network, so that data can find its way to it. Your phone has one on the café Wi-Fi, the server hosting a website has one, your router has one. The classic form (IPv4) looks like `192.168.1.10`: four numbers from 0 to 255 separated by dots.

Every packet of data travelling the internet carries a destination IP address and a sender IP address, exactly like an envelope with two addresses. Routers along the way read the destination and pass the packet closer, hop by hop. When you open a website, your browser first asks DNS to turn the name into an IP address, then sends its request there.

There are two kinds. A **public IP address** is visible to the whole internet and is usually assigned to your home connection by your provider. A **private IP address** (like the `192.168.x.x` range) only works inside your local network; many devices share one public address through NAT. Because the world ran out of IPv4 numbers, the newer **IPv6** uses much longer addresses such as `2001:db8::1`, with room for every device on the planet.

## An analogy

A postal address. The mail carrier does not know who you are, but with the street and number the letter arrives, and the sender's address on the back lets you reply.

## Keep in mind

- IPv4 addresses look like `192.168.1.10`; IPv6 addresses are longer, like `2001:db8::1`.
- Public IPs are reachable from the internet; private IPs only work inside your local network.
- Your IP usually reveals your rough location and your internet provider, not your name.
- DNS exists so people type names, not IP addresses.

## Go deeper

- [What is my IP address? (Cloudflare)](https://www.cloudflare.com/learning/dns/glossary/what-is-my-ip-address/)
- [IP address (MDN glossary)](https://developer.mozilla.org/en-US/docs/Glossary/IP_Address)
- [IP address (Wikipedia)](https://en.wikipedia.org/wiki/IP_address)

## Related terms

- [Wi-Fi](https://tidbit.legios.com.ar/wi-fi/): Networking over radio waves: the internet without the cable, within a few rooms.
- [Server](https://tidbit.legios.com.ar/server/): A computer whose job is to answer requests from other computers, all day, every day.
- [Router](https://tidbit.legios.com.ar/router/): The box that connects your devices to each other and to the internet.
- [Packet](https://tidbit.legios.com.ar/packet/): The small chunk every piece of internet data is cut into before it travels.
- [Internet](https://tidbit.legios.com.ar/internet/): A worldwide network of networks that lets any connected device reach any other.
- [Web browser](https://tidbit.legios.com.ar/web-browser/): The app that fetches web pages from the internet and draws them on your screen.
- [DNS](https://tidbit.legios.com.ar/dns/): The internet's phone book: it turns names like wikipedia.org into IP addresses.
- [NAT](https://tidbit.legios.com.ar/nat/): How a whole home or office shares one public IP address on the internet.