When you translate it out it bits it’s the number of bits that are active in the net mask
0000 0000 0000 0000 0000 0000 0000 is a /0
1111 1111 1111 1111 1111 1111 0000 0000 is a /24
1111 1111 1111 1111 1111 1111 1100 0000 is a /26
And since it’s used for matching, it follows how many there are.
Edit: typed that quickly, but to expand it further, take a /24 subnet, that is 255.255.255.0, if you look above each group of 8-bits can cover 0-255, so you in essence by having 24 bits turned on that’s what you want for an exact match. You’re basically saying “the first three octets need to exactly match”
Yeah, but why is CIDR notation like that? You put a bigger number at the end and your subnet becomes smaller? Why would you want that?
When you translate it out it bits it’s the number of bits that are active in the net mask
0000 0000 0000 0000 0000 0000 0000 is a /0
1111 1111 1111 1111 1111 1111 0000 0000 is a /24
1111 1111 1111 1111 1111 1111 1100 0000 is a /26
And since it’s used for matching, it follows how many there are.
Edit: typed that quickly, but to expand it further, take a /24 subnet, that is 255.255.255.0, if you look above each group of 8-bits can cover 0-255, so you in essence by having 24 bits turned on that’s what you want for an exact match. You’re basically saying “the first three octets need to exactly match”