The Emperor's Proclamations: IPv4 Subnet Masks Made Simple
IP Subnetting - IT Tech Blog
SOLVED: 17. What is the network address and subnet mask (in CIDR notation) of the hidden (xxx.xxx.xxx.xxx/xx) subnet? The whole network has a network address and subnet mask of 192.168.0.0/23. 192.168.0.0/25 192.168.0.128/25
networking - How exactly is a subnet mask used when determining where to send a packet to? - Super User
How to Find Your Subnet Mask: PC, Mac, Linux, Android & More