Public IP vs Private IP vs IPv6: Networking Made Easy With Real Examples

Have you ever wondered how your phone, laptop, and smart TV can all use the same Wi-Fi connection to access the internet? Or why does your computer show one IP address while a website sees a different one?

The answer becomes easier to understand when you learn the difference between Public IP vs Private IP vs IPv6. These terms are closely related, but they do not describe exactly the same thing. Public and private IP addresses refer to how an address is used and reached across networks, while IPv6 is a newer version of the Internet Protocol designed to provide a much larger address space.

This guide explains each concept with everyday examples, private IP ranges, a practical NAT walkthrough, and troubleshooting steps you can try on your own computer.

What You Will Learn

By the end of this guide, you will be able to:

• Explain the difference between public IP addresses, private IP addresses, IPv4, and IPv6.
• Identify the three private IPv4 address ranges defined by RFC 1918.
• Describe how Network Address Translation (NAT) helps devices access the internet.
• Recognize common IPv6 address types and understand where they are used.
• Check your computer’s IP configuration and identify possible network issues.

1. What Is an IP Address?

An Internet Protocol (IP) address is a numerical address assigned to a network interface. It helps devices identify the source and destination of packets as data moves between networks.

Think of sending a parcel. The parcel needs a destination address, and the delivery service needs enough information to move it toward that destination. IP addressing plays a comparable role in digital communication, although actual packet delivery also depends on routing, network configuration, and other protocols.

For example, a home network might contain these addresses:

• Laptop: 192.168.1.10
• Smartphone: 192.168.1.11
• Smart TV: 192.168.1.12

These are private IPv4 addresses. Your router can use them to distinguish devices on the local network.

IP addresses come in two major versions: IPv4 and IPv6. Public and private addressing are separate concepts that help explain how addresses are used.

2. What Is a Public IP Address?

A public IP address is an address that can be used for globally routed communication on the internet, subject to routing, firewall, and network policies. It is commonly assigned to an internet-facing router or directly to a device by an internet service provider or network operator.

Imagine opening a website from your home. Your router sends traffic toward the internet, and the public-facing address may be the address that the website’s server sees as the source of your connection.

A public IP address is useful for services that need to communicate across the internet, such as web hosting, remote access, and internet-facing applications.

Example of a public IP address

Suppose a small business hosts a website on a server with a public IP address. A customer in another country can potentially reach that server using its public address, provided the service is running and the network permits the connection.

However, having a public IP address does not automatically make a device accessible to everyone. Firewalls, access rules, routing, and service configuration still determine whether incoming connections are allowed.

Common uses of public IP addresses

• Hosting websites and internet-facing applications
• Providing public-facing services to remote users
• Connecting networks to internet service providers
• Supporting remote access when appropriate security controls are configured

3. What Is a Private IP Address?

A private IP address is used inside a private network, such as a home, school, office, or internal business network. Private IPv4 addresses are not globally routed across the public internet as ordinary destination addresses.

For example, your laptop may use 192.168.1.10 to communicate with a printer on the same Wi-Fi network. The printer does not need its own public IPv4 address for that local communication.

Private IPv4 address ranges are defined in RFC 1918.

The three private IPv4 address ranges

These ranges are frequently used in networking exercises and certification exams.

A common mistake: not every address beginning with 172 is private. The private block runs from 172.16.0.0 through 172.31.255.255. For example, 172.20.5.10 falls inside the private range, while 172.40.5.10 does not.

Why do networks use private IP addresses?

Private addressing lets organizations reuse the same address ranges in separate networks. A home router, for instance, can assign private addresses to many devices without requiring a separate public IPv4 address for every device.

It also gives administrators flexibility when organizing devices into subnets. Still, private addressing by itself is not a security system. Firewalls, access controls, software updates, and sensible network design remain essential.

4. How Does NAT Connect Private Devices to the Internet?

Network Address Translation (NAT) allows a router or gateway to translate IP addresses between networks. In many home networks, a related technique called Port Address Translation (PAT) lets several devices share one public IPv4 address by tracking different connections using port information.

Consider this example:

• Laptop’s private address: 192.168.1.10
• Phone’s private address: 192.168.1.11
• Router’s public IPv4 address: 203.0.113.25

The public address above comes from a documentation-only range and is used here as an example, not as a real service address.

What happens when you open a website?

Step 1: Your device creates a connection. The laptop sends a request from its private address toward the website.

Step 2: The router processes the traffic. If NAT/PAT is configured, the router records connection information and translates the source address and, where needed, the source port.

Step 3: The request travels outward. The website receives a request whose visible source address is typically the router’s public IPv4 address.

Step 4: The response returns. The router checks its translation state and forwards the response to the correct device on the local network.

A simplified view looks like this:

Laptop (192.168.1.10) → Home Router (public IPv4) → Website

Your phone can use the same public IPv4 address at the same time because the router keeps track of separate connections.

NAT is not the same as a firewall, although routers often provide both functions. NAT also does not guarantee that a network is secure. Security depends on the rules and services configured on the devices and gateway.

5. What Is IPv4?

IPv4 stands for Internet Protocol version 4. It uses 32-bit addresses, normally written as four decimal numbers separated by periods.

Example: 192.168.1.10

Each of the four numbers represents eight bits and can range from 0 to 255. IPv4 supports about 4.3 billion possible 32-bit address values, although some are reserved or unavailable for ordinary host assignment.

IPv4 remains widely used in homes, businesses, data centers, and internet infrastructure. Private IPv4 addressing and NAT have helped networks continue operating despite the limited supply of globally unique IPv4 addresses.

6. What Is IPv6?

IPv6 stands for Internet Protocol version 6. It was developed to succeed IPv4 and provides a much larger address space by using 128-bit addresses.

An IPv6 address is usually written as groups of hexadecimal digits separated by colons.

Example: 2001:db8::10

The 2001:db8::/32 block is reserved for documentation and examples, so this address is suitable for learning but not for identifying a real public server.

IPv6’s much larger address space supports the growth of connected devices and allows network designers to use a different addressing approach. IPv6 is specified in RFC 8200, while its addressing architecture is described in RFC 4291.

Common IPv6 address types

• Global Unicast: Generally used for globally routed IPv6 communication.
• Unique Local: Intended for local communication within private networks; the relevant address block is fc00::/7.
• Link-Local: Used for communication on the local link, commonly with addresses from fe80::/10.

An IPv6 interface can have more than one address. For example, a device may use a link-local address for communication with neighboring devices and a global unicast address for broader connectivity.

Does IPv6 need NAT?

IPv6 does not inherently require NAT to conserve addresses in the way that many IPv4 networks use NAT. A network can assign globally routable IPv6 addresses to devices and control access through routing and firewall policies.

That does not mean every IPv6 device is automatically reachable from the internet. Firewall rules, routing, and service configuration still matter. IPv6 networks may also use translation technologies for specific compatibility or network-design needs.

7. Public IP vs Private IP vs IPv6: What Is the Difference?

One important distinction makes this topic easier: public and private describe address use, while IPv4 and IPv6 describe protocol versions.

This table does not mean IPv6 is always public. IPv6 includes several address types and scopes, including link-local and unique-local addresses. Similarly, an IPv4 address is not public simply because it is written in dotted-decimal format.

8. How to Check Your IP Address on Windows

You can inspect your computer’s local network configuration without installing additional software.

1. Press Windows + R.
2. Type cmd and press Enter.
3. Enter the command ipconfig.
4. Find the network adapter you are currently using.
5. Review the IPv4 Address, IPv6 Address (if shown), and Default Gateway fields.

For example, if you see:

• IPv4 Address: 192.168.1.10
• Default Gateway: 192.168.1.1

your computer is using a private IPv4 address and a local gateway address.

This command shows addresses configured on your device; it does not necessarily show the public IP address that an external website sees. To check the public-facing address, you can consult your router’s status page or a reputable IP-checking service.

Also remember that a network may assign an IPv6 address even when IPv4 is present. Seeing both is normal on a dual-stack network.

9. Practical Troubleshooting: What Does Your Address Tell You?

Imagine a laptop can access a printer on the home network but cannot open websites. Its IP address alone will not reveal the entire cause, but it gives you useful clues.

Situation A: The computer has a private IPv4 address

An address such as 192.168.1.25 is normal on many home networks. It does not mean the computer is disconnected from the internet. Check whether the default gateway is present and whether other devices can access websites.

Situation B: The computer has an address beginning with 169.254

An IPv4 address in the 169.254.0.0/16 range is a link-local address, commonly assigned automatically when a device cannot obtain an IPv4 address through DHCP. It is not one of the RFC 1918 private ranges.

Check the Wi-Fi or Ethernet connection, DHCP service, router, and network adapter settings. On a managed network, contact the administrator before changing configuration.

Situation C: The computer has an IPv6 address but a website does not load

First, determine whether the device has usable connectivity, a default route, and working DNS resolution. The presence of an IPv6 address alone does not prove that the network has working IPv6 internet access. Some networks use IPv4 and IPv6 together, while others may provide only one protocol to a particular device.

Situation D: You cannot connect to a device using its private IP address

Confirm that both devices are on networks that can communicate, that the address is correct, and that the destination service is running. Check local firewall rules and subnet configuration as well. Two devices having private addresses does not automatically mean they can reach each other across every network boundary.

10. Common Misconceptions to Avoid

Myth 1: A private IP address means the device has no internet access.
Not necessarily. A router can translate traffic from private IPv4 devices to a public IPv4 address.

Myth 2: Every address beginning with 172 is private.
Only the RFC 1918 block from 172.16.0.0 to 172.31.255.255 is private.

Myth 3: IPv6 always means a public address.
IPv6 includes global unicast, unique-local, and link-local address types, among others.

Myth 4: NAT makes a network completely secure.
NAT is an address-translation mechanism, not a replacement for firewall rules, secure configurations, or endpoint protection.

Myth 5: IPv4 and IPv6 cannot operate together.
They can coexist on a dual-stack network, where devices and network infrastructure support both protocols.

11. Test Your Understanding

Try these questions before checking the answers.

Question 1: Which of the following is within an RFC 1918 private IPv4 range?

A. 8.8.8.8
B. 172.20.10.5
C. 172.40.10.5
D. 203.0.113.8

Question 2: How many bits are in an IPv6 address?

A. 32
B. 48
C. 64
D. 128

Question 3: What does NAT commonly help a home router do?

A. Replace DNS
B. Allow private IPv4 devices to share a public IPv4 address
C. Encrypt every packet
D. Convert every IPv4 address into IPv6

Question 4: A Windows computer shows 192.168.1.25 after running ipconfig. What can you reasonably conclude?

A. The address is in a common private IPv4 range.
B. The computer definitely has no internet connection.
C. The address must be public.
D. The computer is using IPv6 only.

Answers: 1 — B; 2 — D; 3 — B; 4 — A.

If you missed a question, revisit the private address ranges, the NAT example, or the section on checking your IP configuration.

Conclusion

Understanding Public IP vs Private IP vs IPv6 becomes much simpler when you separate two ideas: how an address is used and which IP version it belongs to. Public IPv4 addresses support globally routed communication, private IPv4 addresses help organize internal networks, and IPv6 provides a much larger address space with its own address types and operating model.

The most useful next step is to examine the addresses on a real device. Run ipconfig, identify the local address and default gateway, and compare what you see with the private ranges in this guide. Connecting the concepts to an actual network makes them easier to remember and apply when troubleshooting.

Frequently Asked Questions

1. What is the main difference between a public IP and a private IP?

A public IP address can be used for globally routed communication, subject to network policies. A private IPv4 address is intended for internal network use and is not ordinarily routed across the public internet.

2. Is 192.168.1.1 a public or private IP address?

It is a private IPv4 address because it falls within 192.168.0.0/16, one of the private ranges defined by RFC 1918.

3. Is IPv6 better than IPv4?

IPv6 provides a much larger address space and supports modern internet addressing requirements. Which protocol works best in a particular situation depends on compatibility, network support, configuration, and application requirements.

4. Can a device have both IPv4 and IPv6 addresses?

Yes. A device on a dual-stack network can use both IPv4 and IPv6. It may have several addresses for different interfaces and communication scopes.

5. Does a private IP address protect me from hackers?

A private address is not a complete security measure. Firewalls, access controls, secure device configuration, updates, and monitoring are important for protecting a network.

6. How can I find my public IP address?

You can check your router’s internet or WAN status page or use a reputable IP-checking website. The address shown on your computer by ipconfig is usually its local interface address, not necessarily the public-facing address.