An IP (Internet Protocol) address is a unique identifying number assigned to any device connected to a computer network or the internet. IP addresses allow different devices to communicate and identify each other on local networks or globally over the internet.
As a webmaster with over 15 years of experience, I‘ve worked extensively with IP addresses and understand their critical role in networking and online infrastructure. Here, I‘ll provide an in-depth guide on everything you need to know about IP addresses.
IP Address Format
An IP address consists of a string of numbers separated by periods. There are four sets of numbers in an IP address, ranging from 0 to 255.
For example, a valid IP address could be:
Each of the four numbers in an IP address is known as an octet. So technically, IP addresses are made up of four octets separated by periods.
Due to the range of 0-255 for each octet, there are over 4 billion possible IP addresses in the original IPv4 system.
Private vs Public IP Addresses
If your device connects to both a local network and the internet, it will have two IP addresses assigned:
Private IP Address: Used internally on your local network
Public IP Address: Used to connect to the wider internet
Your home or office router will assign devices a private IP address typically in the ranges of:
For example, your computer may have a private IP address of 192.168.1.5 when connected to your home WiFi.
To find your private IP, you can use the
ipconfig command on Windows or
ifconfig on Mac/Linux.
Your public IP address is assigned by your Internet Service Provider (ISP). This allows your local network to communicate with devices globally over the internet.
You can easily find your public IP by googling "What is my IP address?". Your current public IP will be shown in the search results.
Websites also have public IP addresses associated with their domain name, assigned by their hosting provider.
IP Addresses vs Domain Names
IP addresses are just numbers, which can be hard to remember. Domain names provide an easy-to-remember way for humans to identify networks, websites, and devices.
The Domain Name System (DNS) acts as the phonebook of the internet. It matches easy-to-remember domain names to their corresponding IP addresses.
When you type a domain name in your browser, DNS looks up the IP address for that domain and directs you to the right location.
Your WordPress site itself only knows its domain name – it doesn‘t know its own IP address. This allows changing hosting providers without affecting your domain name.
Dynamic vs Static IP Addresses
Most home and small business internet connections use dynamic IP addressing. This means your public IP address can change periodically, automatically assigned by your ISP from a pool of available IPs.
Larger organizations and websites typically use static IP addresses that do not change. This provides consistency, especially for handling email delivery and DNS resolution.
If you want to host your own website, you‘ll likely need to purchase a dedicated static IP from your ISP to assign your web server.
Here are two examples illustrating the difference:
Dynamic IP: Your home internet connection, with an IP that changes, like 184.108.40.206.
Static IP: A company‘s web server at a static IP of 220.127.116.11 that never changes.
The IPv4 and IPv6 Protocols
The original IP protocol version is IPv4, which provides the format of four octet numbers like 192.168.1.1.
IPv4 allows for about 4 billion possible IP addresses – not enough anymore for the exponential growth of the internet.
A new 128-bit IPv6 protocol was created to provide vastly more addresses. An IPv6 address looks like:
- Provides approximately 340 trillion trillion trillion unique addresses
- Addresses are 128-bits vs 32-bits for IPv4
- Adoption has grown over 30% in last 5 years to about 25% of internet traffic
IPv6 ensures we have enough IP addresses to satisfy demand well into the future as more devices continue to come online. Understanding the differences between IPv4 and IPv6 is key knowledge for network engineers and webmasters alike.
Real-World Uses of IP Addresses
IP addresses enable just about everything we do online, even though we rarely see them. Here are some examples of how they work behind the scenes:
- Loading a webpage – DNS resolves the domain to its IP address to find the right server
- Sending an email – The mail server uses the recipient‘s IP address to deliver the email
- Downloading a file – Your computer connects to the server IP to transfer the data
- Video call – Devices use IP addresses to stream audio/video between participants
As you can see, IP addresses play a fundamental role that makes networking and internet communications possible. Both IPv4 and the new IPv6 provide the vital numbering system that underpins our digital world.
I hope this detailed guide helps explain the key role and functionality of IP addresses. Let me know if you have any other questions!