Excellent article. But am I missing something or does this sentence have one of those typos spell check doesn't catch?
"That network only contains two usable IP addresses, one, 192.168.1.25/30, for the router LAN side and one, 192.168.0.26/30 for the host itself."
Wouldn't the host IP be 192.168.1.26?
And while I understand why a /30 subnet has only 2 usable addresses, I'm sure I would learn a great deal from an article you wrote about CIDR.