08 -Understanding CIDR Notations
CIDR notations were pretty confusing for me at first, but with continuous use and study it became more understandable. I hope to share some insight on this topic.
CIDR Notations (Classless Inter-Domain Routing) is a way of representing the available range for an IP address in a network. The notation is usually in the form of a slash (/) after the IP address e.g. 10.0.0.0/24.
A simple rule of thumb to remember is “the higher the CIDR Notation the smaller the number of available IP addresses (hosts)”. For instance an IP with a CIDR of 10.0.0.0/24 will have an available 256 host/subnets, while 10.0.0.0/12 will have an available 1,048,576 host. This will come in handy when you’re trying to setup a VPC for a cloud infrastructure.
While there are ways to calculate the number of hosts available to a particular CIDR range, a more time effective way can be to use online calculators or get a table containing the number of available address to a CIDR. See a sample below :)
