One thing you will see when working with subnet mask is a slash followed by the
number of digits belonging to the the network ID.
Subnet mask: 255.255.255.0 will be /24
Subnet mask:255.255.0.0 will be /16
So you may see something like this:
This means it has the subnet mask of 255.255.0.0
This becomes very helpful when you have a a subnet like 255.254.0.0 because the
second octet has part of the network ID and part of the host ID. So this will have a /15
which will show you that the first 15 digits belong to the network ID without you having to
do any decimal to binary converting
I hope I explained it good enough. Let me know if you want a further explanation on this .
Edited by Jake001, 10 March 2015 - 09:03 AM.