IP Subnet Mask Quick Cheat Sheet ~ Ask The Admin

Wednesday, January 09, 2008

IP Subnet Mask Quick Cheat Sheet

So I 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:

Check out this IP Subnet Tool Calculator - MINT! http://www.syrex.co.za/ipcalc/