If you understand Subnetting, then you probably know that the CIDR notation of /24 correlates to the Subnet Mask of 255.255.255.0. But did you also know both of those correlate to the Wildcard Mask of 0.0.0.255?
This video picks apart Wildard Masks, what they are, and how they are used. We’ll cover the following concepts:
- Basic Definition of Wildcard Masks
- Binary Conversions (CIDR to Subnet to Wildcard)
- Special Wildcard Masks: /32 and /0
- Easier Conversions between Subnet Masks and Wildcard Masks
- What can you do with a Wildcard Mask?
- Determine if two IP addresses are in the same Subnet
- Identify IP addresses in a particular Subnet
- How is a Wildcard Mask different from a Subnet Mask?
- Discontiguous Wildcard Masks
This video is a follow up to a video I released earlier in the month discussing Binary. Both this video on Wildcard Masks, and the aforementioned Binary videos are pre-cursors to a video on Access Control Lists (ACLs) that I am working on.
Really useful explanation of wildcard masks. I especially liked how the article connects CIDR notation, subnet masks, and wildcard masks instead of speed stars treating them as separate concepts. The examples around /32, /0, and discontiguous masks also make the topic much easier to understand. This is a great reference for anyone learning subnetting and preparing to work with ACLs.