Turning an Idle Home Computer into a Zero-Cost Server — The Early Friction
Hosting fees were adding up, so I turned on a home server — then hit SSL certificates and domain walls
There was no grand reason. Hosting fees were just getting on my nerves.
As apps accumulated, I started noticing the cloud bills. Around ₩40,000–50,000 a month. Not a huge amount, but when I thought about running multiple side-project apps indefinitely, watching that money leave every month started to bother me. Then it hit me. I had a computer at home sitting idle, just running — couldn’t I use that?
So I turned it on.
But a home server is different from cloud the moment you start it.
Cloud gives you one IP and you’re done. A home computer hides behind a router. On top of that, my home runs on a KT residential line, so the public IP isn’t even static. To allow inbound connections, I’d need to open ports, attach a domain, and get an HTTPS certificate. Everything the cloud handled automatically — now manual.
And then I hit a wall with HTTPS.
The site came up, but the padlock (HTTPS certificate) in the address bar just wouldn’t appear. I’m the kind of person who dives in without studying first, so I spent a while thinking I must have misconfigured something.
Turned out the culprit was somewhere else entirely. The iptime.org domain that my router provides by default was the problem. A CAA record on that parent domain was blocking certificate authorities entirely — Let’s Encrypt couldn’t issue a certificate. It wasn’t my misconfiguration; the domain itself was locked. (The full story of tracking down that CAA record is in the next post.)
So I switched to DuckDNS.
Free, no CAA restrictions, and it automatically tracks a dynamic public IP — meaning it follows along even when my KT line’s IP changes. The moment I switched, the blocked certificate went through. “This is it,” I thought.
After using it for a while, I bought a real domain. hansaiam.com on Cloudflare, for my mom’s art gallery.
Once I attached the domain, a thought came to me: “So can I ditch duck now?”
The answer was no. Even a purchased domain still needs someone tracking the dynamic IP behind the scenes — and that someone is duck. So I pointed my domain to the DuckDNS address via CNAME. When the IP changes, duck catches it, and my domain follows duck. Duck keeps working invisibly as the IP tracker.
That’s how an idle computer at home became a zero-cost-per-month server. Right now, multiple apps are running on it.
If you have a computer at home that’s just sitting there running, you don’t have to prep extensively — you can just turn it on and start bumping into things. How I set up multiple apps coexisting on one server (Caddy), and the security hardening that started the moment I opened it to the outside — that’s in the next posts.