Have you always wanted to learn how to subnet IPv4 addresses? Already know how to subnet, but want to improve your speed or accuracy with subnetting? You aren't alone! I've met many people that want to improve their skills in the "art" of subnetting, so I decided to do a quick post to share some resources on how to do just that.
How to subnet a network (pdf) - Beginners guide to subnetting, somewhat technical though.
How to subnet an address the easy way - This page provides a handy shortcut to figure out what your network address is based on the subnet mask.
How to subnet a network - Introductory level, somewhat in-depth on the binary stuff, but doesn't provide many examples.
How to subnet in your head - 90 page presentation with great info.
Now, you might be saying, "a subnet calculator is easier," and you are right, they are. But if you want to learn how to do subnetting in your head really quick, it just takes a lot of practice. If you have an awesome resource that isn't listed here, feel free to post a link to it in the comments.