Subnetting – Part 2: Real Examples That Make It Click!

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Subnetting is a fundamental skill for network engineers, CCNA candidates, and IT professionals. In this article, we dive into practical subnetting examples to help you master the concept beyond theory.

You Should Know: Practical Subnetting Steps

Example 1: Breaking Down a Class C Network

Given the network 192.168.1.0/24, divide it into 4 subnets.

Step-by-Step Calculation:

1. Determine the number of subnet bits needed:

  • To create 4 subnets, use the formula:
    2^n ≥ Number of Subnets 
2^2 = 4
  • n = 2 (additional subnet bits).

2. New Subnet Mask:

  • Original mask: /24 (255.255.255.0)
  • New mask: /26 (255.255.255.192)

3. Subnet Ranges:

  • Subnet 1: 192.168.1.0 – 192.168.1.63
  • Subnet 2: 192.168.1.64 – 192.168.1.127
  • Subnet 3: 192.168.1.128 – 192.168.1.191
  • Subnet 4: 192.168.1.192 – 192.168.1.255

Verification Command (Linux/Windows):

ping 192.168.1.65  Tests connectivity within Subnet 2

Example 2: Subnetting a Class B Network

Given 172.16.0.0/16, divide it into 8 subnets.

Step-by-Step Calculation:

1. Subnet Bits Required:

2^3 = 8

– n = 3 (additional bits).

2. New Subnet Mask:

  • Original: /16 (255.255.0.0)
  • New: /19 (255.255.224.0)

3. Subnet Ranges:

  • Subnet 1: 172.16.0.0 – 172.16.31.255
  • Subnet 2: 172.16.32.0 – 172.16.63.255
  • Subnet 3: 172.16.64.0 – 172.16.95.255
  • Subnet 4: 172.16.96.0 – 172.16.127.255
  • Subnet 5: 172.16.128.0 – 172.16.159.255
  • Subnet 6: 172.16.160.0 – 172.16.191.255
  • Subnet 7: 172.16.192.0 – 172.16.223.255
  • Subnet 8: 172.16.224.0 – 172.16.255.255

Verification Command (Linux):

ifconfig eth0 172.16.32.10 netmask 255.255.224.0  Assigns an IP in Subnet 2

What Undercode Say

Subnetting is essential for optimizing network performance and security. Mastering it helps in:
– Efficient IP allocation
– Reducing broadcast traffic
– Enhancing network segmentation

Useful Commands for Network Admins:

  • Linux:
    ip addr show  Displays current IP configuration 
route -n  Shows routing table
  • Windows:
    ipconfig /all  Detailed network info 
route print  Displays routing table

Prediction

As networks evolve, subnetting will remain critical, especially with IPv6 adoption. Automation tools will simplify subnetting, but manual calculations will still be foundational for troubleshooting.

Expected Output:

A structured subnetting guide with practical examples, verified commands, and real-world applications.

References:

Reported By: Tabish4hmad Subnetting – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

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