Public vs. Private IP Address: How Are They Different?

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Public vs Private IP Address: How Are They Different? – A Quick Guide

An IP address works as an online identifier that helps websites correctly transfer information to you. There are two kinds of IP addresses: public and private.

• A public IP address is assigned to you by your internet service provider. It’s a unique alphanumeric string used by your router to identify you to websites and apps online.
• A private IP is assigned by your router to devices on your local area network. It helps the router relay information received from websites to the correct device. Private IP addresses needn’t be unique since and can be reused.

Public and private IPs differ in the functions they perform and their uniqueness. They also differ in terms of traceability: public IP addresses can be tracked by sites, ISPs, and the government. Conversely, private IP addresses are only visible to other devices on your local network and cannot be tracked by websites or ISPs. Hackers can also use your private IP to track down connected devices.

Hence, it makes sense to safeguard both your public and private IP addresses by using a virtual private network. A VPN encrypts your internet activity and changes your IP address. This helps prevent tracking, surveillance and hacking.

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Do read the rest of the article for a more detailed breakdown of the difference between public and private IP addresses!

An IP address is a numeric or alphanumeric identifier assigned to a router or device. It helps direct traffic on the internet to the correct location. Your postal address is a real-world parallel of an IP address. It helps the postal department deliver letters to the correct recipient.

While most users know about an IP address, many aren’t aware that there are two kinds of IP addresses. These are private IP addresses and public IP addresses. Both play an important role in connecting users to the internet.

This article breaks down the differences between public and private IP addresses. We explain the utility of each and highlight the role they can play in keeping your internet activity private and secure.

Public IP Address vs. Private IP Address: Overview

A public IP address refers to the unique identifier assigned to your internet connection by your internet service provider. Your router uses your public IP address to identify you to the rest of the internet.

This ensures that websites, emails, and other content on the internet reach you correctly.

On the other hand, the private IP address identifies different devices connected to the same local network. Once your router has received information from the global network, it needs to know which device to send it to.

The private IP address helps the router identify different devices on your network and forward the information correctly.

The following table captures the major differences between a public and a private IP address. A breakdown of both kinds of IP addresses is provided in the next section.

CategoryPrivate IP AddressPublic IP AddressUtilityUsed to communicate between devices on a local networkUsed to communicate with sites and servers on the internetRange

• 10.0.0.0 — 10.255.255.255
• 172.16.0.0 — 172.31.255.255
• 192.168.0.0 — 192.168.255.255

Alpha-numeric combinations not assigned to private IP addressesPriceFree: assigned by your routerNot free: assigned by your internet service provider at a priceTraceabilityTraceable by other devices on the local networkTraceable by ISPs, advertisers, governments, and hackersHow to viewUsing system settings and preferencesSearch for “What is my IP address” on GoogleUniquenessNot unique, resued by different routersCompletely unique code not used by other devices

What Is a Public IP Address?

A public IP address is an IP assigned to your router by your internet service provider. It’s also known as an external IP address since websites, servers, and apps on the global network use it to identify you. The visualization below should help understand how a public IP address works.

A public IP address acts as your gateway to the internet, and you usually can’t go online without one. Your public IP address must be visible to sites and web pages to correctly communicate with websites.

What Is a Private IP Address?

Your router sends data packets from connected devices to servers on different websites. Once packets are received, they need to be forwarded to the relevant device. With several devices connected to the router at one time, it uses your private IP address to distinguish and relay this information.

It can do this by using your device’s private IP address, a numerical identifier assigned to each device on the local network. A private IP address is also known as the local IP address.

Think of the private IP address as the room, floor, or dorm number on your postal address. Once the letter arrives at your building, the specific room/floor number helps ensure the letter reaches you instead of any other residents.

Unlike a public IP address, your private IP address is not visible to other websites. Instead, it’s only visible to other devices on your network. You can usually check the private IP addresses of all devices connected to the router via its settings.

What Are the Differences Between Private and Public IP Addresses?

Now that we know what public and private IP addresses are, let’s understand the key differences between them.

Utility

As the previous section illustrates, both public and private IP addresses serve different purposes. While your router uses the public IP address to identify you to websites on the internet, the private IP address is used to identify different devices on your local network.

However, both private and public IP addresses work together to provide internet connectivity. Websites on the internet send information to your router using a public IP address. Your router then forwards this information to the relevant device’s private IP address using network access translation (NAT).

But why are private IP addresses needed in the first place? Why can’t each device have its own unique external IP? To answer this question, let’s first understand what IPv4 is. IPv4 is the most widely used internet protocol. It was launched in 1970 and comprises 32-bit numeric strings.

As a result, it can only support 4 billion unique addresses, which is obviously less than the number of connected devices out in the world today. Therefore, allotting private IP addresses to devices on the same network is a way to conserve IPv4 addresses.

However, we are in the midst of a transition to IPv6 which comprises 128-bit alphanumeric strings. Hence, IPv6 supports 340 undecillion possible combinations, which should be more than enough for the foreseeable future!

Predetermined ranges

Both public and private IP addresses fall within certain predetermined ranges of numeric strings to make the entire framework systematic and logical. The Internet Assigned Numbers Authority (IANA) distributes private IP addresses to companies worldwide. IP addresses used by some of the leading router manufacturers are:

ManufacturerPrivate IP addressBelkin / SMC192.168.2.1Cisco192.168.10.2 or 192.168.1.254 or 192.168.1.1D-Link / Netgear192.168.0.1Linksys192.168.1.1

Conversely, public IP addresses usually comprise numeric strings not assigned to any private ID addresses. Moreover, each public IP address is unique and cannot be reused while private IP addresses are regularly reused across different routers.

How to check your public and private IP address

At this stage, you’re probably curious about the public and private IP addresses currently assigned to you. Well, it’s rather easy to view your public IP address. You can search for “what is my IP address?” on Google, or just visit NordVPN to check it.

In fact, the table below should show your IP address and location. While this may seem cool, it opens up possibilities for tracking and surveillance on the internet (discussed in the next section).

IP detailsYour detailsIP addressISP or organizationCity (approximated)AreaCountryTime zone

function geoip(json) {
var div = document.getElementById(‘ip-adres’);
div.innerHTML=”+json.ip+”;
var div = document.getElementById(‘land’);
div.innerHTML=”+json.country+”;
var div = document.getElementById(‘stad’);
div.innerHTML=”+json.city+”;
var div = document.getElementById(‘provincie’);
div.innerHTML=”+json.region+”;
var div = document.getElementById(‘tijdzone’);
div.innerHTML=”+json.timezone+”;
var div = document.getElementById(‘organisatie’);
div.innerHTML=”+json.organization+”;
}

Determining your private IP address requires a few more steps. You can follow the steps outlined below to check your private IP address on Mac and Windows.

Determining your private IP address on a Mac:

1. Open System Preferences
2. Select Network
3. Choose the network you’re currently connected to, i.e. WiFi or Ethernet
4. Check your private IP address below the ‘Status’ column (pictured below)

View your private IP address on Windows:

1. Press the Windows key and the letter “R” to open up Run.
2. Type “cmd” in the blank field that appears to open up a command prompt window.
3. Type “ipconfig” in the blank in the command prompt window.
4. The IPv4 address listed on the page is your private IP address.

Traceability

As we mentioned earlier, websites and servers use the public IP address to identify you online. Hence, the public IP must be visible to these sites. While this is important to facilitate the flow of information from websites to your router, it also opens up possibilities for surveillance and tracking.

Many websites, advertisers, governments, and ISPs use your public IP address to track and monitor your activity.

Conversely, a private IP address is visible only to other devices on your network. This usually does not lead to any problems or security risks.

However, if a hacker or third-party gains access to your local network, the private IP address can be used to target different devices on your network and infect them with malware, such as killware, worms, and trojans.

Hence, it makes sense to hide both your public IP address to protect your anonymity online. Using a virtual private network is an easy way to do this. A VPN encrypts your internet activity and changes your public IP address. As a result, your internet activity can no longer be tracked online.

Furthermore, a VPN also hides your device’s private IP from other devices on the network. It also helps avoid state-imposed censorship and geo-blocks imposed by streaming websites, such as Netflix and Hulu.

We highly recommend NordVPN as it’s safe and reliable, offers excellent speeds, and has servers all over the world.

There are other ways to change a public IP address as well, such as by using a proxy. However, this isn’t as effective as using a VPN.

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Public vs. Private IP: Conclusion

This article explains the difference between public and private IP addresses. Both are vital to internet connectivity but serve very different purposes. A public IP address helps identify you to websites on the internet.

However, a private IP address identifies different devices on the same network. It’s sensible to use a VPN to hide both your public and private IP address as it helps avoid possible surveillance and tracking.

Public vs Private IP Address: Frequently Asked Questions

We’ve answered some of the most frequently asked questions about the difference between a public and private IP address in the section below. Please let us know if there are any questions we haven’t addressed by posting in the comments section!

What are the differences between a public and private IP address?

A public IP address is used by your router to identify you to websites on the internet. This helps ensure that the websites can send information to the correct recipient. A public IP address is unique and is assigned by your internet service provider.

A private IP address is used by your router to identify different devices on your local network. Unlike a public IP address, it can only be viewed by other devices on your network and needn’t be unique. These are just some of the several differences between public and private IP addresses.

How does a private IP address become a public IP address?

Your router uses network access translation (NAT) to map the different private IP addresses assigned to devices on your local network to a single public IP address. While a private IP address doesn’t become a public IP address using NAT, the process helps ensure that information is routed to the correct device.

Is 192.168 a private or public IP?

192.168 is usually a private IP address. The range of numbers between 192.168.0.0 and 192.168.255.255 is reserved for private IP addresses. The Internet Assigned Numbers Authority distributes these numbers to router manufacturers.

How do I determine my public and private IP?

Go to google and type in “what is my IP” to determine your public IP. As long as you’re not using a VPN, the IP that comes up in the search results is your public IP address.

Finding out your private IP address requires you to play around with system settings a little bit. On a Mac, for example, you’ll need to follow the steps listed below to determine your private IP:

1. Open “System Preferences.”
2. Select “Network.”
3. Choose the network you’re currently connected to, i.e. Wi-Fi or Ethernet.
4. Your private IP address should be listed just below the “Status” column.

You can get more information in our article on the main differences between public and private IP addresses.

Is public IP better than private IP?

Both of them serve very different purposes, so one can’t be better than the other. A public IP helps relay information and connect to a website server, whereas a private IP is used for connecting to the router.

Mohit Chawdhry
Author

Tech journalist

Mohit is a legal and public policy researcher whose work focuses largely on technology regulation. At VPNOverview, he writes about cybersecurity, cryptocurrencies and sports events.