Part 9 — How I Dug Myself Into a Home DNS Hole

By David Relich May 17, 2026

There is a very specific kind of danger that comes with personal projects.

Not the obvious danger.

Not:

  • deadlines

  • bugs

  • broken deployments

  • mysterious Docker errors

No.

The truly dangerous moments begin with innocent thoughts like:

Hmm… there’s probably a cleaner way to do this.

That exact thought recently appeared while working on the mobile version of Needle.

The problem itself seemed simple enough.

The app could already connect:

  • locally inside my home network

  • remotely over the internet

I had even implemented logic to switch between the two. And technically speaking? It worked beautifully. There was only one tiny issue.

I suddenly realised I was teaching the app about network topology.

The app knew:

  • local URLs

  • remote URLs

  • switching logic

  • connectivity states

  • fallback behaviour

And while all of that sounded clever at first, it also felt suspiciously like the beginning of future suffering.

Because now the app had opinions about:

  • Wi-Fi

  • LANs

  • internet routing

  • public access

  • local access

Which raised an uncomfortable philosophical question:

Should an app care where the server physically is?

And honestly? I don’t think it should.

The app should simply know:

This is Needle.

The network infrastructure should handle the rest.

So naturally, instead of continuing work on the actual music app, I disappeared head-first into a DNS rabbit hole.

As one does.

The idea was surprisingly elegant.

Inside my home network:

music.davidrelich.cz
→ 192.168.x.x

Outside my home network:

music.davidrelich.cz
→ public server IP

Same URL.
Same SSL certificate.
Same backend.
Different routing depending on where the request originates.

Which meant:

  • local traffic stays local

  • no unnecessary ISP round-trips

  • no app-side switching logic

  • cleaner architecture

  • less maintenance

  • fewer future headaches

Beautiful.

There was only one small detail.

My TP-Link router had absolutely no idea how to do any of this.

At which point the normal person response would probably be:

Ah well, never mind.

Unfortunately, I am no longer a normal person.

So instead I deployed AdGuard Home on the Raspberry Pi 5 that already runs approximately half of my digital existence.

This led to the traditional homelab experience:

  • Docker port conflicts

  • DNS port conflicts

  • mysterious networking errors

  • discovering that NetBird quietly occupied port 53 on another interface

  • fighting systemd-resolved

  • and learning far more about local DNS than I ever intended to know

At one point I found myself staring at terminal output showing:

127.0.0.53
172.18.x.x
100.x.x.x

…and wondering if I had accidentally opened a Stargate instead of configuring DNS.

Still, after enough tweaking, container wrangling, and mild existential discomfort, something magical happened.

I pointed my router’s DNS settings to the Raspberry Pi.

Then I ran:

dig music.davidrelich.cz

And suddenly my own infrastructure replied.

Not Google.
Not Cloudflare.
Not my ISP.

Mine.

That was one of those quietly satisfying moments where you realise:

Oh no… I actually understand this now.

Which is both empowering and mildly terrifying.

Then came the final step.

I added a local DNS rewrite:

music.davidrelich.cz
→ 192.168.x.x

And just like that:

  • local traffic remained inside the house

  • the app no longer cared where it was

  • the same URL worked everywhere

  • and the architecture suddenly became dramatically cleaner

Of course, there was also an unexpected side effect.

AdGuard Home blocks ads.

Meaning I somehow went from:

I want Needle to behave more elegantly on local Wi-Fi

to:

Congratulations, you are now the administrator of your household DNS infrastructure.

Which is not a sentence I expected to say this year.

Then again, I also didn’t expect to build:

  • a desktop music player

  • a backend

  • a web player

  • an Android app

  • and now an iPhone app

…simply because modern streaming platforms annoyed me enough.

So honestly?

At this point, deploying my own DNS server feels completely on-brand.

Holy crap, it works.