What is an IP address?

An IP address, or Internet Protocol address, is a unique identifier assigned to each device connected to a network. It’s used by computers to communicate with each other and to access the Internet.

An IP address is like a mailing address, but for computers. Connected devices don’t send letters; they send packets of data, using the IP address to identify both the sender and the recipient. Every device connected to your home network has a local IP address.

IP addresses are generally formatted as a series of four numbers separated by dots (for example, 192.168.1.1). In your home, all IP addresses probably start the same way, with only the last number changing for each device.

Difference between local IP address and public

In various Raspberry Pi and Linux projects, you may notice that you can have two different types of IP addresses:

• Local IP addresses are used on your private network, such as your home Wi-Fi. They are assigned by your router to each device connected to it (computers, TVs, smartphones, etc.). This allows them to communicate internally.
• Public IP addresses are how the outside world sees every device connected to the Internet from your home network. They all use the same one, the one assigned by your ISP (Internet Service Provider).

In short, the principle is the same, it’s just a different network. The Internet is simply a huge network with the whole world connected to it.

Difference between IPv4 and IPv6

IP addresses can exist in two different formats (versions): IPv4 or IPv6.

IPv4 is the most commonly used, with the format I mentioned earlier (like 192.168.1.1). The problem is that this is limited, with “only” 4 billion unique addresses possible, which is no longer enough for the whole world.

That’s why IPv6 addresses were created, they are much longer and offer a virtually unlimited number of addresses (like 2001:db8:3333:4444:5555:6666:7777:8888).

Related articles and tutorials

• 7 Easy Ways to Find your Raspberry Pi IP Address
• How to Set Static IP Address on Ubuntu Server (Step-by-step)
• 3 Simple Ways to Disable IPv6 on Raspberry Pi