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ANDing It Out

Lesson 13 of 46 in Coddy's IP Addressing and Subnetting course.

Here is what a machine actually does with the mask: a bitwise AND between address and mask. Wherever the mask has a 1, the address bit survives; wherever it has a 0, the result is 0. What comes out is the network address.

Only the partial octet needs real work. For 192.168.10.130 with mask 255.255.255.128: the first three octets pass through untouched, and in the last octet 130 (10000010) AND 128 (10000000) keeps only the top bit: 128.

Result: 192.168.10.128. Every routing decision on Earth starts with this operation.

Challenge

Beginner

AND the address 192.168.10.130 with the mask 255.255.255.128 and print the resulting network address.

Expected output:

192.168.10.128

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 MaskANDing It OutRecap - 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