What is network CIDR notation?

Figure out how many IP addresses are in a network CIDR with this easy to remember example

Take all of the IP addresses and divide it by 2. Then divide that by 2. Then divide that by 2

/24 is 256 addresses. If you subtract 1 to a /23 then you divide 256/2 = 128. If you add one to /25 then you double 256 addresses to 512.

Start with a couple CIDRs you can remember and divide or multiple by two until you get the CIDR you need.

a /32 is only 1 IP address.

0:14 - a /1 CIDR
0:28 - a /2 CIDR
0:49 - a /3 CIDR
1:26 - why /32 is 1 IP
1:43 - /24
1:57 - /23

[ryanlee]

Great explanation! Thanks for that, mate! 😀

[svmoki]

thank you so much for putting in an understandable way, you deserve more views

[gruvboxer]

I think there was some confusion in the example about /24.

A /23 mask will have more IP addresses than /24 because there's one less fixed bit.

/23 = 512
/24 = 256
/25 = 128

[AnowarHossain-tzqb]

Excellent, Thanks for sharing this video.