It helps subnet design and makes list of subnets.
You can look for good subnet mask easily because this App shows the below information for your entries.
- number of subnets
- number of host addresses per subnet
The list of subnets is made when IP address is entered too. Characteristic (Subnet Zero, All-Ones Subnet, Super net) of networks is indicated with icons on list of subnets. Sliders for masks and keypad for IP address helps quick entry.