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Which Subnet Am I In

Lesson 25 of 46 in Coddy's IP Addressing and Subnetting course.

The most common exam and real-life question: given an address and a prefix, which subnet does it belong to? With the block size trick it takes seconds.

Take 192.168.1.150/26. Block size 64, boundaries 0, 64, 128, 192. The last octet 150 falls between 128 and 192, so the subnet is 192.168.1.128 and its broadcast is one short of the next boundary: 192.168.1.191.

Find the boundary at or below the address; that is always the network.

Challenge

Beginner

The machine 192.168.1.150/26: print its network address, then its broadcast address, each on its own line.

Expected output:

192.168.1.128
192.168.1.191

Try it yourself

Terminal

All lessons in IP Addressing and Subnetting

1Bits and Binary

Numbers as Bits Binary to Decimal Powers of Two Recap - Binary Warm-up

4CIDR Notation

Goodbye Classes Reading CIDR Block Sizes Recap - CIDR Reading

7Special Addresses

Private Ranges Loopback Link-Local Zero and Broadcast

10Capstone - The Office

The Floor Plan Sizing Each Team Carving the Block The Router's View Recap - Ship the Plan

2IPv4 Anatomy

Four Octets The 32-Bit View Network and Host Valid or Not Recap - Read an Address

5Inside a Subnet

Network Address Broadcast Address Usable Hosts First and Last Host Recap - Subnet Facts

8Planning Networks

Right-Sizing VLSM Step by Step Allocation Order Checking for Overlap Recap - Plan a Network

3The Subnet Mask

What a Mask Does Mask to Prefix Prefix to Mask ANDing It Out Recap - Mask Basics

6Subnetting Drills

The Block Size TrickWhich Subnet Am I InSplitting a /24 Splitting Again Recap - Subnetting Drills

9IPv6 First Steps

Why IPv6 Reading IPv6 Prefixes in IPv6 Recap - IPv6 Basics

Practice on your own: Terminal playground