Which Three IPv4 Network Addresses Are Private IP Addresses? (Choose Three.) Explained

In the world of networking, understanding private IP addresses is fundamental. If you’re preparing for networking certifications like Cisco’s CCNA or CompTIA Network+, you may have come across questions like “which three IPv4 network addresses are private IP addresses? (choose three.)” This article breaks it down clearly to help you understand private IP address ranges, their significance, and how to recognize them in certification exams.

What Are IP Addresses?

IP (Internet Protocol) addresses are unique identifiers assigned to each device connected to a network. They enable devices to communicate with each other across the internet or within a local network.

There are two main versions of IP addresses:

• IPv4 (Internet Protocol version 4): 32-bit address space (e.g., 192.168.1.1)
• IPv6 (Internet Protocol version 6): 128-bit address space (e.g., 2001:0db8::1)

This blog focuses solely on IPv4 private addresses.

What Are Private IP Addresses?

Private IP addresses are reserved IP address ranges used within local networks (such as homes, businesses, or data centers). These addresses are not routable on the public internet. Devices using private IPs communicate with the outside world using Network Address Translation (NAT) via a public IP.

The main goal of using private IPs is to preserve the limited number of IPv4 public addresses and secure internal traffic from external exposure.

The Three Private IPv4 Address Ranges

The Internet Assigned Numbers Authority (IANA) has reserved the following three IP ranges for private use:

1. 10.0.0.0 – 10.255.255.255
   • This provides 16,777,216 addresses (Class A)
   • Used in large organizations and enterprises
2. 172.16.0.0 – 172.31.255.255
   • Offers 1,048,576 addresses (Class B)
   • Common in medium-sized networks
3. 192.168.0.0 – 192.168.255.255
   • Contains 65,536 addresses (Class C)
   • Widely used in home and small office networks

These three blocks are the correct answers to the question:
“Which three IPv4 network addresses are private IP addresses? (choose three.)”

Any other IPv4 range outside of these blocks is considered public and routable on the internet.

Why Are Private IP Addresses Important?

1. Security: Private addresses cannot be accessed directly from the internet, enhancing internal network security.
2. Address Conservation: Reduces the need for a unique public IP for every device.
3. NAT Compatibility: Works with routers using NAT to translate private IPs into a single public IP.

Examples of Private IP Addresses

Here are a few examples of private IP addresses from each block:

• From 10.0.0.0/8:
  • 10.1.1.1
  • 10.255.0.3
• From 172.16.0.0/12:
  • 172.16.10.25
  • 172.31.255.254
• From 192.168.0.0/16:
  • 192.168.1.1
  • 192.168.100.100

All of these are valid private IPs.

Misconceptions to Avoid

• 172.32.0.0 is not a private IP. It’s outside the valid private Class B range.
• 192.167.x.x or 193.x.x.x addresses are public, not private.
• Only the specific blocks listed above are considered private by global standards (RFC 1918).

RFC 1918 – The Standard for Private IPs

RFC 1918 is the official document that outlines the use of private IP addresses. It designates the exact IPv4 address blocks reserved for internal use. This ensures consistency across global networks.

The RFC defines the private ranges as:

Private vs Public IP Address – Key Differences

Where Are Private IPs Used?

• Home Networks: Wi-Fi routers assign private IPs to devices.
• Corporate LANs: Thousands of users use private IPs within an enterprise.
• Data Centers: Internal servers communicate via private addressing.
• Cloud Environments: VMs often use private IPs and are exposed via NAT or load balancers.

How Private IPs Work with NAT

When a private IP wants to communicate with a public website (e.g., www.google.com), the router uses NAT to replace the private source IP with the router’s public IP. The response returns to the router, which then forwards it to the correct internal device.

This allows multiple private IP devices to access the internet using one public IP.

How to Identify Private IPs in a Network

To check your device’s IP address:

• Windows:
  Open Command Prompt and type ipconfig
• Linux/macOS:
  Use ifconfig or ip addr

If your IP begins with 10., 172.16 to 172.31, or 192.168., it’s a private IP.

Common Mistakes in Exams

When answering the question “which three IPv4 network addresses are private IP addresses? (choose three.)”, avoid these traps:

• Picking addresses like 172.32.x.x – that’s public
• Choosing 127.0.0.1 – it’s a loopback, not a private IP
• Selecting 169.254.x.x – that’s APIPA, not a private IP

Final Thoughts

Knowing the answer to “which three IPv4 network addresses are private IP addresses? (choose three.)” is more than just passing an exam—it’s understanding a foundational concept in networking.

These addresses are used in nearly every organization, from home setups to global enterprises. By mastering this topic, you’re building essential knowledge for network administration, security, and cloud computing.

For more questions like these and study resources, visit StudyDumps Official and explore our full collection of certification guides and dumps.

Sample MCQ Questions and Answers

Q1. Which three IPv4 network addresses are private IP addresses? (Choose three.)
A. 10.0.0.0
B. 172.32.0.0
C. 172.16.0.0
D. 192.168.1.0
Correct Answers: A, C, D

Q2. Which IP address is NOT a private IP?
A. 192.168.0.1
B. 10.10.10.10
C. 8.8.8.8
D. 172.20.1.1
Correct Answer: C

Q3. What is the private IP range for Class B networks?
A. 172.0.0.0 – 172.255.255.255
B. 172.16.0.0 – 172.31.255.255
C. 172.32.0.0 – 172.63.255.255
D. 172.15.0.0 – 172.20.255.255
Correct Answer: B

Q4. Why are private IP addresses not routable over the internet?
A. They’re only used in IPv6 networks
B. NAT blocks their communication
C. IANA reserves them for local use
D. They use incorrect subnet masks
Correct Answer: C

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