Before you put a Pi-hole in your house — the hardware is the cheap part
This is the version of DNS filtering that runs inside your house. Installing it is not the hard bit. The hard bit is that when it goes down, so does everything else.
The DNS filtering article compared two approaches and said a DNS service is the right answer for most households. So when is the other one worth it?
When you would rather the record of those questions never left your house. That is the reason Pi-hole exists, and the price of it is that you become responsible for keeping it alive.
What actually changes
With a DNS service, a record of “which addresses were looked up” sits with that company. A tool you switched on to reduce tracking has created a new record somewhere else. It is not a large problem, but it is the one some people want gone.
Pi-hole makes that decision inside your house. Neither the question nor the answer leaves.
What you need
One machine that stays powered on. The name makes people assume they have to buy a Raspberry Pi. They don’t.
- A Raspberry Pi, the most common choice
- A mini PC or laptop you no longer use
- One container on a home server you already run
The electricity is close to nothing. At Raspberry Pi scale, leaving it on around the clock is not the kind of cost you notice. The exact figure depends on the machine, and it is not one we have measured, so no number here.
The part that matters more than installation
Here is the whole point of this article.
Once you put the Pi-hole’s address into your router as the DNS, every device in the house goes to that machine when it needs an address. If the machine is off, nobody gets an answer. The internet doesn’t get slower. It stops.
The same happens if the power lead gets knocked out, if the SD card wears out, or if an update takes longer to reboot than expected. And whoever is at home at the time only knows that “the internet is broken”, not why.
So prepare two things before you start.
- Put a secondary DNS in alongside it. Router DNS settings usually have two fields. Pi-hole in the first, a public DNS in the second, and the house stays online when the Pi-hole dies. The trade is that filtering lapses for that period
- Write down your original settings. Reverting takes thirty seconds, but without a note those thirty seconds become an hour
The first of those is a compromise. Perfect filtering means leaving the second field empty, which turns that one machine into a single point of failure for the whole house. If other people live there, take the compromise.
The order to set it up
- Install Pi-hole on the machine. The install script handles most of it
- It will ask you to set a static IP. Do it. If that address changes later, the router setting no longer matches and you get exactly the failure above
- Open the web admin page and check it is answering
- Point one device at it and live with that for a few days
- Only then change the router setting so the whole house uses it
Don’t skip step 4. Apply it house-wide first and you have no way to find out what broke.
Start with the default block list
Pi-hole lets you add lists to widen what gets blocked. Get greedy here and you get exactly the side effects covered in the DNS article: app stores that won’t open, payments that stall halfway.
Spend a week on the defaults, and widen only if nothing has broken.
What the admin page gives you
There is an unexpected benefit once it is running. You get a list of which device asked for what, and how many times, today.
If the device list tells you who is connected, this tells you what they are doing. You will watch something you assumed was idle call its manufacturer every few minutes, and that list may turn out to be the real value of the tool.
In short
| Question | Answer |
|---|---|
| Why this instead of a DNS service | The record of your questions stays in the house |
| Do I need a Raspberry Pi | No. Any machine that stays on |
| Biggest risk | If it goes down, the house internet goes down |
| How to prepare | Add a secondary DNS, even though filtering lapses |
| Don’t miss this at install | The static IP |
| Where to start | One device for a few days, then the house |
| Which block lists | Defaults. Widen later |
The hardware is the small part of this decision. The real cost is adding a single point of failure to your house, and it is only worth it when you can carry that.