I have been taught that the subnet mask for classful addresses are always A = 255.0.0.0 B = 255.255.0.0 C = 255.255.255.0 so does that mean that subnet masks do not necessarily mean the IP address is subnetted?
a very unrelated comment, but when I see this video was posted 7 years ago, I always think it's from 2012 or something. Meanwhile that would be 2017. I'm getting older :')