Help with [int ipaddr or ipaddr/cdir]

[jeffnoone]

This is a basic question about network notation, but would appreciate help, or link to relatively easy tutorial on this

I am entering some PC addresses in the Services/UPnp area under "User specified permissions"

So I need to understand how to use "[int ipaddr or ipaddr/cdir]"

I use a 192.168.0.x network at home with pfSense at 192.168.0.251
My PC's start at 192.168.0.2 and upwards

SO I believe these two are correct
192.168.0.75/31 - specifies just one PC at 192.168.0.75
192.168.0.0/24 - specifies all PC's, routers and printers in the 192.168.0.1-254 range

BUt what does 192.168.0.75/32 mean
?
And similarly , there seem to be options of 192.168.0.75/32 - any meaning?
Also 192.168.0.75/30 or 192.168.0.75/29 or 192.168.0.75/28 - any meaning?

Is there any way to name say three or four PC's in a consecutive range with this technique?

Any help appreciated
Jeff

[SeventhSon]

I think this might help you:
http://en.wikipedia.org/wiki/Subnetwork#Subnet_and_host_counts

192.168.0.75/31 - specifies just one PC at 192.168.0.75
192.168.0.0/24 - specifies all PC's, routers and printers in the 192.168.0.1-254 range

If you want just one IP in your subnet it's a /32.