What is an IP Address? Complete Guide

An IP address (Internet Protocol address) is a unique number assigned to every device connected to the Internet. Think of it as your device's postal address — it's how other computers find and communicate with yours. Without IP addresses, the Internet as we know it wouldn't exist.

How IP Addresses Work

When you type a website address like miip.link into your browser, here's what happens:

1. Your browser sends a DNS query asking: "What is the IP address of miip.link?"
2. The DNS server responds with the IP (e.g., 104.21.50.120)
3. Your browser connects to that IP address using the TCP/IP protocol
4. The server sends the webpage back to your IP address
5. Your browser renders the page

This entire process takes milliseconds. Without IP addresses, this communication would be impossible — like trying to send a letter without an address on the envelope.

IPv4 vs IPv6

IPv4

IPv4 uses 32-bit addresses, written as four numbers separated by dots (e.g., 192.168.1.1). Each number ranges from 0 to 255. This gives approximately 4.3 billion unique addresses, which sounds like a lot but isn't — the world ran out of new IPv4 addresses in 2019.

IPv4 address structure:

• Network portion: Identifies the network
• Host portion: Identifies the specific device
• Subnet mask: Determines where the split between network and host occurs

Learn more about subnet masks in our subnet mask guide.

IPv6

IPv6 uses 128-bit addresses, written as eight groups of hexadecimal numbers separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). This provides 340 undecillion addresses — more than enough for every grain of sand on Earth.

IPv6 advantages:

• Practically unlimited addresses
• Better routing efficiency
• Built-in security (IPSec)
• No need for NAT (Network Address Translation)
• Simplified header for faster processing

You can check if you have IPv6 at miip.link — if you see a long address with colons, you're using IPv6.

Public IP vs Private IP

Public IP

Your public IP is visible from anywhere on the Internet. It's assigned by your Internet Service Provider (ISP) and is what websites see when you visit them. Every device on the same WiFi network shares the same public IP through a process called NAT.

You can see your public IP right now at miip.link.

Private IP

Your private IP exists only on your local network. It's assigned by your router and is only visible to other devices on the same network. Private IP ranges are defined by RFC 1918:

• 10.0.0.0 — 10.255.255.255 (Class A: 16+ million addresses)
• 172.16.0.0 — 172.31.255.255 (Class B: 1+ million addresses)
• 192.168.0.0 — 192.168.255.255 (Class C: 65,534 addresses)

Your home network almost certainly uses the 192.168.x.x range. Read more about this in our public vs private IP guide.

How IP Addresses Are Assigned

When you connect to the Internet, your ISP assigns you an IP address from their pool. This can happen in two ways:

• DHCP (Dynamic Host Configuration Protocol): The most common method. Your router assigns private IPs to each device on your local network, and your ISP assigns a public IP to your router. These IPs can change over time. Learn more about dynamic vs static IPs.
• Static configuration: Some servers and network devices have fixed IPs that never change. This is essential for web servers, email servers, and other services that need a constant address.

IP Address Classes

Special IP Addresses

• 127.0.0.1 (localhost): Points to your own device. Essential for development and testing. More about localhost →
• 0.0.0.0: Represents "all network interfaces." Used in server configuration to listen on all interfaces.
• 255.255.255.255: Broadcast address — sends data to all devices on the local network.
• 169.254.x.x: APIPA — self-assigned addresses when no DHCP server is available.

Security and IP Addresses

Your IP address reveals information about you:

• Approximate location: City and country (not your exact address)
• ISP: Which Internet Service Provider you use
• Connection type: Whether you're on a mobile network, corporate network, etc.

However, your IP alone cannot reveal your name, address, or personal identity. For better privacy, use a VPN to hide your IP address.

The IPv4 Address Exhaustion Problem

With only 4.3 billion IPv4 addresses and billions of Internet-connected devices, we've run out of new IPv4 addresses. Solutions include:

• NAT: Multiple devices share one public IP (most home routers do this)
• IPv6 adoption: The long-term solution, with virtually unlimited addresses
• CGNAT (Carrier-Grade NAT): ISPs sharing one public IP across many customers

FAQ

Can someone track me with my IP?

Your IP reveals your approximate location (city-level) and your ISP, but not your exact address or personal identity. IP geolocation has city-level accuracy, not street-level.

Does my IP change?

Most ISPs assign dynamic IPs that change periodically. Static IPs stay the same and usually cost extra.

How do I find my IP?

Visit miip.link — your public IP appears instantly, along with your ISP, city, and country.

What's the difference between IP and MAC address?

Your IP address is logical and changes depending on the network. Your MAC address is physical and permanently assigned to your network card. IPs operate at the network layer (Layer 3), while MACs operate at the data link layer (Layer 2).