moz screenshot 2 IP Subnet Mask Quick Cheat Sheet

Besides the fact that I am studying for another Microsoft test and staring at subnets all day long – I also get asked on a regular basis how many addresses can i get from a /24 subnet or what does 255.255.255.0 mean.

Let me break it down for you real quick like:

When you use 255.255.255.0 as your subnet you are limiting yourself to a network containing all the same ip’s except for the last number. Like 192.168.1.0 where the 0 changes. And using 255.255.0.0 Would limit you to the last two digits changing like 192.168.0.0 . Are you with me? It gets a little more complex with different subnets but here is a quick breakdown for you:


Hosts Netmask Amount of a Class C
/30 4 255.255.255.252 1/64
/29 8 255.255.255.248 1/32
/28 16 255.255.255.240 1/16
/27 32 255.255.255.224 1/8
/26 64 255.255.255.192 1/4
/24 256 255.255.255.0 1
/23 512 255.255.254.0 2
/22 1024 255.255.252.0 4
/21 2048 255.255.248.0 8
/20 4096 255.255.240.0 16
/19 8192 255.255.224.0 32
/18 16384 255.255.192.0 64
/17 32768 255.255.128.0 128
/16 65536 255.255.0.0 256

Check out this IP Subnet Tool Calculator – MINT! http://www.syrex.co.za/ipcalc/
ips IP Subnet Mask Quick Cheat Sheet

_TheSubnettingAdmiN_