# IP Address (Internet Protocol Address)

URL: https://softwaredictionary.org/terms/ip-address
Category: Networking
Last updated: 2026-09-30
In Turkish: IP Adresi

In short: An IP address is a numeric label assigned to each device on a network so that data can be routed to it, much like a postal address for a house.

## What is an IP address?

An IP address is a unique identifier given to every device that connects to a network using the Internet Protocol, such as a laptop, phone, server, or router. It tells other machines where to send data and where incoming data came from. Without IP addresses, computers on the internet would have no way to find each other.

Two versions are in use today. IPv4 addresses are 32-bit numbers written as four decimal parts, like `192.168.1.10`, which allows about 4.3 billion addresses. IPv6 addresses are 128-bit numbers written in hexadecimal, like `2001:db8::1`, and were introduced because the world was running out of IPv4 addresses. Routers read the destination IP address on each packet and forward it step by step toward its target.

Think of an IP address like a street address: the postal service does not care who lives in the house, only where to deliver the letter. Addresses can be public, meaning reachable from the internet, or private, such as `10.0.0.5` or `192.168.0.2`, which work only inside a home or office network. A router using network address translation (NAT) lets many private devices share one public address.

IP addresses are often confused with domain names. A domain name like `example.com` is a human-friendly label, and DNS translates it into the IP address that computers actually use. An IP address is also different from a MAC address, which is a hardware identifier for a network card that is only used on the local network.

## Key takeaways

- An IP address identifies a device on a network so data can be routed to it.
- IPv4 uses 32-bit addresses like `192.168.1.10`; IPv6 uses 128-bit addresses like `2001:db8::1`.
- Private addresses work only inside a local network; public addresses are reachable from the internet.
- DNS translates human-friendly domain names into IP addresses.
- Many devices receive their IP address automatically, so it can change over time.

## Example: Working with IP addresses on the command line

```bash
# Show the IP addresses of this machine (Linux)
ip addr show

# Look up the IP address behind a domain name
dig +short example.com

# Check whether a device on the local network is reachable
ping -c 3 192.168.1.1
```

## Frequently asked questions

**What is the difference between IPv4 and IPv6?**

IPv4 uses 32-bit addresses, which allows about 4.3 billion unique addresses, while IPv6 uses 128-bit addresses, which allows vastly more. IPv6 was created because IPv4 addresses ran out, and today most networks support both.

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

A public IP address is reachable from the internet and is unique worldwide. A private IP address, such as `192.168.1.20`, is used only inside a local network, and the router translates it to a public address when traffic goes out.

**Can two devices have the same IP address?**

Not on the same network at the same time, because data would not know which device to reach. However, the same private address, such as `192.168.1.2`, is reused in millions of separate home networks.

## Sources

- [RFC 791: Internet Protocol](https://www.rfc-editor.org/rfc/rfc791.html)
- [RFC 8200: Internet Protocol, Version 6 (IPv6) Specification](https://www.rfc-editor.org/rfc/rfc8200.html)

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