What Difference: Public vs Private IP Addresses

In the world of computer networking, IP addresses play a crucial role in facilitating communication between devices. An IP address, or Internet Protocol address, is a unique identifier assigned to each device connected to a network. It allows devices to send and receive data, access websites, and exchange information. IP addresses are classified into two main types: public IP addresses and private IP addresses. Understanding the difference between these two types is essential for maintaining privacy, security, and efficient network communication.

What is a Public IP Address?

A public IP address is an outward-facing address that is assigned to a network router by an Internet Service Provider (ISP). It is the IP address used by devices to connect to the internet and communicate with other devices on different networks. Public IP addresses are unique and globally recognized, allowing devices to be accessed from anywhere in the world.

When you access a website, send an email, or engage in any online activity, your device uses its public IP address to establish a connection with the internet. This address acts as a gateway, enabling communication between your device and the vast network of devices and servers on the internet.

Public IP addresses are commonly used by businesses, organizations, and public-facing servers such as websites, VPNs, and DNS servers. They are essential for providing remote access to devices, configuring servers, and hosting online services.

How to Find Your Public IP Address

Finding your public IP address is a simple process. There are several methods you can use to discover this information:

1. Using Google: One of the easiest ways to find your public IP address is to search "what is my IP address" on Google. The search results will show your public IP address or you can find out your IP address at WhatIsMyIPAddress.
2. Command Line (Linux): Linux users can use the hostname or ifconfig command in the terminal to retrieve their public IP address.
3. Command Line (Windows): Windows users can open the Command Prompt and enter the command ipconfig to view their public IP address.
4. Settings (MAC): Macos users click on the WiFi icon → click on WiFi settings and then → go to Details. Their will see public IP addresses. 

It's important to note that public IP addresses are assigned by ISPs and can change over time, especially for devices with dynamic IP addresses. If you need a static IP address that remains constant, you may need to contact your ISP and request one.

Public IP Address Ranges

Public IP addresses are assigned from specific IP address ranges to ensure uniqueness across the internet. These ranges are allotted to different organizations and ISPs. Here are some of the commonly used public IP address ranges:

Public IP Address Range
1.0.0.0 - 9.255.255.255
11.0.0.0 - 100.63.255.255
100.128.0.0 - 126.255.255.255
128.0.0.0 - 169.253.255.255
169.255.0.0 - 172.15.255.255
172.32.0.0 - 191.255.255.255
192.0.1.0/24
192.0.3.0 - 192.88.98.255
192.88.100.0 - 192.167.255.255
192.169.0.0 - 198.17.255.255
198.20.0.0 - 198.51.99.255
198.51.101.0 - 203.0.112.255
203.0.114.0 - 223.255.255.255

These ranges ensure that every device connected to the internet has a unique public IP address. They are regulated and managed by the Internet Assigned Numbers Authority (IANA) to prevent address conflicts and ensure efficient routing of data across the internet.

What is a Private IP Address?

A private IP address is an internal address assigned by a network router to devices within a private network. It enables communication between devices within the same network and is not accessible directly from the internet. Private IP addresses are used for local network communication and are not globally unique.

Unlike public IP addresses, which are unique across the internet, private IP addresses can be reused within different private networks. This allows for more efficient allocation of IP addresses within private networks, as the same private IP address can be used by different devices in different networks without conflicts.

Private IP addresses are commonly used in home networks, office networks, and local area networks (LANs). They provide a secure and isolated environment for devices within the network to communicate and share resources.

How to Find Your Private IP Address

Finding your private IP address depends on the operating system you are using. Here are the steps to find your private IP address on different platforms:

Windows:

1. Press the Windows key and type Command Prompt to open the Command Prompt application.
2. In the Command Prompt window, type ipconfig and press Enter.
3. Look for the IPv4 Address under the network adapter you are connected to. This is your private IP address.

Mac:

1. Click on the Apple menu and select System Preferences.
2. In the System Preferences window, click on Network.
3. Select the network connection you are using (Wi-Fi, Ethernet, etc.)
4. Your private IP address will be displayed under the Status section.

Linux:

1. Open the Terminal application.
2. Type ifconfig or ip addr and press Enter.
3. Look for the IP address listed under the network adapter you are connected to. This is your private IP address.

Private IP Address Ranges

Private IP addresses are assigned from specific IP address ranges designated for private use. These ranges are reserved by the Internet Assigned Numbers Authority (IANA) and are not routable on the internet. Here are the commonly used private IP address ranges:

Private IP Address Range

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 ensure that private IP addresses do not conflict with public IP addresses and remain unique within the private network. Devices within the same private network can communicate with each other using their private IP addresses.

Key Differences Between Public and Private IP Addresses

Now that we have explored the concepts of public and private IP addresses, let's summarize the key differences between the two:

1. Scope: Public IP addresses have a global scope and are used to communicate outside the network, while private IP addresses have a local scope and are used for internal network communication.
2. Communication: Public IP addresses allow devices to communicate over the internet, while private IP addresses facilitate communication within a private network.
3. Uniqueness: Public IP addresses are unique and globally recognized, whereas private IP addresses can be reused within different private networks.
4. Origin: Public IP addresses are assigned by ISPs, while private IP addresses are assigned by network routers within the private network.
5. Security: Public IP addresses may require additional security measures due to their exposure to the internet, while private IP addresses are inherently more secure as they are not directly accessible from the internet.
6. Example: An example of a public IP address is 17.5.7.8, while an example of a private IP address is 192.168.1.10.
7. Range: Public IP addresses can be any number outside the private IP address ranges, while private IP addresses fall within the reserved ranges mentioned earlier.

Conclusion

In conclusion, understanding the difference between public and private IP addresses is essential for navigating the world of computer networking. Public IP addresses are globally recognized and used for communication over the internet, while private IP addresses facilitate communication within a private network. Public IP addresses are assigned by ISPs and have a global scope, while private IP addresses are assigned by network routers and have a local scope. By knowing the distinction between public and private IP addresses, you can ensure secure and efficient network communication.