Carving the Block

Lesson 44 of 46 in Coddy's IP Addressing and Subnetting course.

Step three: allocate. Start at the very beginning of 10.20.0.0/23 and place each team's subnet where the previous one ends, largest first.

One new wrinkle: the block is a /23, so it spans two last octets: 10.20.0.0 through 10.20.1.255, 512 addresses in all. Our four subnets need 128 + 64 + 32 + 16 = 240 of them, so everything fits in the first half with room to spare.

Keep the boundary rule in mind as you go: each subnet must start on a multiple of its own size.

Challenge

Medium

Print the four allocations in CIDR notation, one per line, in allocation order: Engineering (/25), Sales (/26), Support (/27), Printers (/28).

Expected output:

10.20.0.0/25
10.20.0.128/26
10.20.0.192/27
10.20.0.224/28

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 TeamCarving the BlockThe 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 Trick Which Subnet Am I In Splitting 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