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What is an IP address

Jay

08 Jun 2009 • 2 min read

What is an IP address?

An IP (Internet Protocol) address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. Think of it as a postal address for your computer or device on the internet.

Types of IP Addresses

IPv4 Addresses

IPv4 addresses are 32-bit numbers typically written in dotted decimal notation, consisting of four numbers separated by dots. Each number ranges from 0 to 255. For example: 192.168.1.1 or 10.0.0.1.

IPv6 Addresses

IPv6 addresses are 128-bit numbers written in hexadecimal notation, separated by colons. They were created to address the limited number of IPv4 addresses available. An example would be: 2001:0db8:85a3:0000:0000:8a2e:0370:7334.

Public vs Private IP Addresses

Public IP Addresses

Public IP addresses are globally unique and routable on the internet. Your Internet Service Provider (ISP) assigns these addresses to your router or modem.

Private IP Addresses

Private IP addresses are used within local networks and are not routable on the internet. Common private IP address ranges include:

10.0.0.0 to 10.255.255.255 (Class A)
172.16.0.0 to 172.31.255.255 (Class B)
192.168.0.0 to 192.168.255.255 (Class C)

How IP Addresses Work

When you want to visit a website, your device needs to know the IP address of that website's server. This process involves:

Your device sends a request to a DNS (Domain Name System) server
The DNS server translates the domain name (like google.com) into an IP address
Your device uses that IP address to establish a connection with the web server
Data is then exchanged between your device and the server

Static vs Dynamic IP Addresses

Static IP Addresses

Static IP addresses remain constant and don't change. They are typically used for servers, printers, and other devices that need to be consistently reachable at the same address.

Dynamic IP Addresses

Dynamic IP addresses are assigned automatically by a DHCP (Dynamic Host Configuration Protocol) server and can change over time. Most home and office devices use dynamic IP addresses.

Finding Your IP Address

To find your device's IP address, you can use various methods:

Windows:

ipconfig

macOS/Linux:

ifconfig

To find your public IP address:

Visit websites like whatismyipaddress.com or use the command:

curl ifconfig.me

Conclusion

IP addresses are fundamental to how the internet works, serving as unique identifiers that allow devices to communicate with each other across networks. Understanding IP addresses is essential for anyone working with networks, whether you're setting up a home network or pursuing a career in IT.