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Understanding Subnetting for Network Security

Aug 14, 2024

Notes on Subnetting Lecture

Introduction

  • Importance of network security
  • Need for subnetting to break a network into smaller segments:
    • Wireless IoT
    • DMZ (Demilitarized Zone)
    • User networks

Episode Context

  • This is Episode 6 of the "You Suck at Subnetting" series
  • Previous episodes provide foundational knowledge for this session
  • Encouragement to watch prior episodes if not yet viewed

Subnetting Basics

  • Subnet mask is crucial in determining network structure
  • Subnet mask reveals:
    • Network bits (1s)
    • Host bits (0s)

Objective

  • Break down the current network into 4 smaller networks using subnetting
  • Understand the need to manipulate subnet masks
    • More networks require borrowing host bits

Steps to Subnetting

  1. Determine how many additional networks are needed
    • Example: for 4 networks, need to borrow bits
  2. Use binary conversion to find out how many bits to borrow
    • Nosferatu for decimal to binary conversion
    • Example: 2 bits borrowed for 4 networks
  3. Modify the subnet mask accordingly
    • Flip borrowed host bits to network bits
  4. Convert the new subnet mask back to decimal notation
    • New mask becomes: 192.168.1.0/26

Finding Network Ranges

  • Calculate the increment based on the new subnet mask
    • Increment = last network bit = 64
  • Network ranges:
    • Network 1: 192.168.1.0 to 192.168.1.63
    • Network 2: 192.168.1.64 to 192.168.1.127
    • Network 3: 192.168.1.128 to 192.168.1.191
    • Network 4: 192.168.1.192 to 192.168.1.255

Host Availability

  • Each of the four networks has a subnet mask of 255.255.255.192 (or /26)
  • Host calculation:
    • 6 host bits available
    • Usable hosts = 2^6 - 2 = 62 usable addresses

Homework Assignment

  • Convert the given network into 5 networks instead of 4
  • Submit subnet mask and network ranges

Final Thoughts

  • Key takeaway: Ability to subnet networks is a vital skill in IT
  • Acknowledgement of IT Pro TV as a valuable resource for further learning
  • Encouragement to continue practicing and learning about subnetting

Conclusion

  • Keep an eye out for future episodes in the series
  • Reminder to check out IT Pro TV for comprehensive training
  • Use code "networkchuck" for discounts on subscriptions.

Full transcript