EasySubnetting.com

Adapted from an article originally published on the Internet by Greg Stanley, MCP, and rewritten by Beau Sanders, this article is designed to help students who need a system to answer subnetting questions while taking certification exams or college networking courses, where calculators and/or tip sheets are not allowed. The writers assume that the reader is familiar with subnetting theory and knows how to count in binary at least to 16 bits. This article was last revised on November 4, 2018.

This document is an excerpt from MCSE Guide to Microsoft® Windows 2000® Networking Certification Edition, written by Kelly Caudle, Walter J. Glenn, and James Michael Stewart. The second edition of this book was published by Course Technology on March 28, 2003 (ISBN: 978-0619186845). This book was written prior to the change allowing the first and last subnets in an incremental range to be used. Beau Sanders revised this excerpt document on November 4, 2108 to reflect the change allowing all subnets in an incremental range to be used.

Cisco tutorial for new network administrators. "This document provides basic information needed in order to configure your router for routing IP, such as how addresses are broken down and how subnetting works. You learn how to assign each interface on the router an IP address with a unique subnet. There are examples included in order to help tie everything together."

This is Chapter 4 from Todd Lammle's excellent study guide for CCNA exam preparation. This 42 page PDF file is an excellent resource for students learning subnetting.

An in depth whitepaper on learning to subnet provided by PrepLogic.

Excellent article on subnetting

Learn how to subnet a subnet and better manage address space when networks have varying numbers of host requirements.

Free account available. Site offers Pro account for a small fee. Subnetting.net is full of free tools designed to help you learn and master subnetting. Check out the Video and Written Tutorials, Practice Questions, and the Subnetting Game to hone your skills. If you’re studying for the CCENT or CCNA exam, the Pro Account provides many additional features including CCENT/CCNA Videos, Labs, and Practice Questions.

An excellent online resource for all things related to subnetting. The web site includes several excellent subnet calculators.

The most extensive subnetting practice site on the web!

Part of a CCNA online training program. A "Premium Membership" is available for a fee.

Practice IPv4 subnetting on this easy to use website.

Great site for many practice subnetting questions. The more you practice subnetting questions, the better you will do on real tests.

This is one of the best free subnet calculators found on the Internet. Click on the “Download Adv Subnet Calculator Now”, complete the contact form, and follow the online instructions

This is a homemade CCNA tip sheet that collects the most important subnet details on one page. This sheet was last revised November 4, 2018.

Charts and tips to help subnetting students focus on the fundamentals and binary math. This sheet was posted on November 5, 2018.

Blank Subnet Worksheet used in our Subnetting Workshop (PDF)