Devices also have a subnet mask, which defines which part of the IP address belongs to the network and which part belongs to the device.

How to Calculate Subnets With Microsoft Excel. IP addresses on your company network consist of three parts: the network address, the host address and the subnet mask.

Here is an example question : Class C, Five Subnets. the book states that always look in the Y column. ofcourse the closest value for 5 subnets is 6.

Is there an easy way (like via a .Net library) that allows me to get the IP address and subnet mask of the local machine that the application is running on?

IP address classes are ignored by assigning subnet masks. You might use Class A address space (10.x.x.x) and use the Class C subnet mask (255.255.255.0) to manage those addresses.