Saturday, June 01, 2019

How To Tell Which CIDR Notation is Bigger

This post is about how to quickly tell which range, represented by CIDR notation is bigger: that is contains a higher number of IP addresses. It is part of series of posts on Tips to Quickly Perform Binary and CIDR Operations.

How to tell which CIDR notation is bigger

Given CIDR notations, be able to tell which is bigger: That is which contains more IP addresses.

Step to answer:
The CIDR notation with the biggest IP prefix, contains the lesser IP address.

This can be deduced in the steps outlined in the post: How To Tell The Count of IP Numbers In a CIDR Notation: the larger the prefix, the less the amount that would be left after it is subtracted from 32 or 128 if IPv6.

Out of the following CIDR prefix: /17, /25, /30 which is the largest and the smallest?
/17 - Largest
/30 - Smallest

I admit, it needs some getting used to, to be able to infer that the smaller number actually depicts a larger range.

Previous post: How To Tell The Count of IP Numbers In a CIDR Notation
Next post: How to quickly tell the first and last ip in a CIDR range

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