In this, our final look at subnetting for now, we’ll examine more “find the subnet” problems, specifically those in which the subnet/host boundary lies within the second or third octets. Here is the powers of two chart: n = 8 7 6 5 4 3 2 1 2n = 256 128 64 32 16 8 4 […]

In the previous editions of “Subnetting Shortcuts”, we solved various types of problems involving subnet masks. This time, we’ll look at some more complex cases, specifically those in which the subnet/host boundary lies within the second or third octets. But first, because our lives would be incomplete without it, here is the powers of two chart: […]

This time, we’ll use the shortcuts to solve some different types of problem. Instead of “find the mask”, this time the challenge is to “find the subnet”. Ready? Here’s the first problem: given a host address of 192.168.1.100 and a subnet mask of “/27”, determine the host’s subnet, the legal range of host addresses on […]

In “Part 3”, we solved a subnet masking problem using shortcuts. This time, we’ll use the shortcuts to solve some additional problems. Here’s the first problem: given an address space of 172.16.1.0/24, divide the network into five subnets, each supporting at least twenty hosts. Here are the steps we’ll use: Using the powers of two chart, […]

In “Part 2”, we solved a subnet masking problem using binary. This time, we’ll look at some helpful shortcuts that can make solving such problems faster and easier for most people (and less error-prone, as well). First, let’s summarize our findings from before. To subnet the 192.168.1.0/24 network into four subnets, each allowing at least fifty […]

In Subnetting Shortcuts– Part One, we reviewed the classful addressing scheme, and the purpose of a subnet mask.  Now let’s look at an example. Let’s say that you’ve been given an address space of 192.168.1.0/24, and you’re asked to subnet the network such that you can have four subnets, each supporting at least 50 hosts. […]

Many CCNA candidates have trouble with subnet masking (and some CCNP candidates, as well!). Over the next few weeks, we’ll learn some shortcuts that make subnet masking calculations easier. But first, a review … Recall that the IPv4 address space is subdivided into five regions, referred to as Class A, B, C, D and E: Class […]