I design electronics for a living, so I am very comfortable with EDA software and blowing up components and releasing the magic smoke within, but I'm very much not comfortable with networks. That gap caught up with me recently when I tried to set up a NAS at home.
The plan was simple in my head: put a NAS built from a 10+ year old PC running TrueNAS and Nextcloud on the network for backups and media, reachable from anywhere through Tailscale, then over time add a pile of little smart-home gadgets I build myself with ESP32 boards (I already have terrarium and aquarium controllers I made), because that is my idea of a fun weekend. Hardware I trust, I can see it, I can burn it. Networks, it turns out, I had been treating like magic that "just works" as long as the wifi icon is full.
The moment I had to give the NAS a fixed address, I had questions I was a little embarrassed by. What is a /24, really? My router hands out 192.168.1.wtf?, so how many devices can I even have? And should my homemade ESP gadgets, which I would not trust further than I can throw them, really sit on the same network as the box holding every photo I own?
So I did the obvious thing and googled it. To be upfront: all of this is googleable, and there are already a dozen good subnet calculators out there. I used several of them. None of what follows is a discovery. It is just the stuff I wish someone had handed me on day one as a hardware guy poking at a home network.
