Differences Between Public and Private IP Addresses

YASH PAL,

Differences Between Public and Private IP Addresses – IP addresses are much like real-life addresses. They help computers understand where they have to go on the Internet to find a particular website. All websites have their own unique IP address that routers and edge devices use to find them. 

Similarly, edge devices (like your computer, smartphone, etc) have their own IP address as well. Since communication on the internet is a 2-way street, website servers also need to know the IP addresses of the edge devices they have to serve the website to.

Quite a simple concept, wouldn’t you say? What complicates things is the distinction between private IP addresses and public IP addresses. The distinction is present due to a variety of reasons. Understanding those reasons, as well as how private and public IP addresses differ from each other, will improve your understanding and knowledge of networking.

What Is an IP Address?

An IP address is a numerical identifier assigned to a device on a network. It allows devices to communicate with each other, whether within a local network or across the internet. Depending on where and how the device is connected, it will use either a public or a private IP address.

Let’s start with the general description of an IP address. It is a numerical identifier assigned to a device on a network that allows other devices on the same network to find and communicate with it. 

Currently, there are two versions of IP addresses. They are called IPv4 and IPv6. 

IPv4 addresses consist of 32-bit addresses. These are written as four segments of numbers separated by dots. For example:

234.68.128.2

This is an IPv4 address. IPv6 addresses have a different notation. They use hexadecimal numbers and are 128-bit addresses. They are written as eight segments of numbers separated by “colon signs”. 

For example: 

2001:db8:85a3:0:0:8a2e:370:7334

The concept of public and private IP addresses is relevant to IPv4. That’s because IPv4 addresses have run out of address space. There are more devices in the world that can connect to the internet than every unique combination of the IPv4 address space. 

IPv6 adoption is quite slow, and even today, much of the internet is still using IPv4 infrastructure. So, to combat the lack of available IPv4 address space, NAT was created. NAT stands for Network Address Translation and is the reason why the concept of public and private IP addresses exists. Let’s learn about them in detail.

What Is a Public IP Address?

When you connect to the internet from your home or office network, you are actually using a public IP address. This address is provided by your ISP, and it is usually assigned to your router.

This public IP address is visible on the internet, and it is what websites, servers, and online services see and use for communicating with your devices.

All the devices that connect to the router in your home or office network to access the Internet use the same public IP address. To the public internet, it appears as if it’s just one device accessing different websites and using various services.

This way, many devices can connect to the internet using just one IP address. So even if the address space is used up, devices can just share a public IP address to connect to the internet.

Public IP addresses are unique worldwide. They are not repeated or reused.

What Is a Private IP Address?

A private IP address is used within a local network, such as a home, school, or office network. The access point (internet-facing router) in these networks has the public IP address, but all the devices connected to it using cables or WiFi have private IP addresses. These addresses are assigned by routers and are not visible on the public internet.

Private IP addresses are used by the router to differentiate which part of incoming traffic needs to go to which device. Without private IP addresses,  all incoming traffic would be sent to all connected devices, and that would congest the network, making it useless.

Private IP addresses have a specific range, and all addresses in this range can be repeated across different networks, but never in the same network. 

The ranges are as follows:

  • 10.0.0.0 – 10.255.255.255
  • 172.16.0.0 – 172.31.255.255
  • 192.168.0.0 – 192.168.255.255

These ranges are reserved exclusively for internal network use and cannot be routed on the public internet. So, if you were to do an IP lookup for any address in this range, you would not get any results.

Common uses of private IP addresses include:

  • Local file sharing
  • Connecting to network printers
  • Managing smart devices within a home or office
  • Communication of devices within the same network.

So, now you should understand. Public IPs enable multiple devices to share one Internet-facing IPv4 address. This saves the limited address space of IPv4. 

However, since all devices need a unique IP for proper communication, the access point router uses private IP addresses (hidden from the Internet) and assigns them to each device in its network. The router knows which traffic is meant for which private IP and ensures that only that device receives it, and prevents cross-talk.

Summary of Key Differences Between Public and Private IP Addresses

The table below provides a quick comparison to make the differences easier to understand:

FeaturePublic IP AddressPrivate IP Address
VisibilityVisible on the internetHidden within a local network
UniquenessGlobally uniqueCan be reused across different networks
AssignmentAssigned by an ISPAssigned by a router
Primary UseInternet communicationInternal network communication
Security ExposureDirectly exposed onlineProtected from direct internet access

How to Find Your Public and Private IP Address

Knowing how to check both your public and private IP addresses can be helpful for troubleshooting, network setup, and security checks. Here’s how you can do that on various platforms.

On Windows

If you are on Windows 10 or 11, then you can use the following methods to check your private and public IP addresses.

  • Private IP address.

Open the Command Prompt and type “ipconfig”. Press “Enter” and wait for the results. In the results, look for the IPv4 address under your active network. That’s your private IP address.

  • Public IP address. 

To check your public IP address, open a browser and visit a trusted website with an What is my IP address tool; it will show you your current public IP address.

On Android

On Android devices, you can check your private and public IP addresses in the following ways.

  • Private IP address.
    Go to Settings → Network & Internet → Wi‑Fi, tap your connected network, and view network details. In most phones, there will be a category called IP address that lists your private IP.
  • Public IP address.

For the public IP address, it is the same as before. Open a browser and use an IP address checker to see your public IP.

On Linux

Here’s how you can check your private and public IP addresses on Linux.

  • Private IP address.
    Open the terminal and run the “ip addr” or “ifconfig” commands to view your local network address.
  • Public IP address.
    As usual, use a browser-based What is my IP address tool to instantly view your public-facing address.

Final Thoughts

Public and private IP addresses work together to keep modern networks running smoothly. While public IP addresses connect users to the wider internet, private IP addresses manage communication within local networks.

Understanding the differences between them not only builds basic networking knowledge but also helps users make smarter decisions about security, connectivity, and troubleshooting.

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