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What DNS is, and why changing it blocks ads

In plain words

Computers do not know what google.com means. They only understand numbers like 142.250.184.14. DNS is the phone book that turns the name into the number. Every single time your device loads anything — a page, an image, an advert — it asks a DNS server "what is the number for this name?"

Normally you use your internet provider's phone book. If you use ours instead, then whenever a page asks for the number of a known advertising or tracking domain, our server answers "that address does not exist" — and the advert never loads. The rest of the page loads completely normally.

What you actually gain

What it does not do

About privacy

Using someone's DNS means they can see which domain names you look up. We run this resolver with query logging kept to what is needed to keep it working, we do not build profiles, and we do not sell or share anything. But you should apply that scepticism to every DNS provider, including your own ISP — who logs the same thing and often for longer. If you would rather not, that is a completely reasonable choice.

The addresses you will need

Keep this section open in another tab while you follow the steps. Which one you need depends on the device — each set of instructions below says exactly which.

Use thisWhere
62.197.221.140Routers, Windows, macOS, Linux, games consoles — anywhere that asks for a numeric DNS server.
dns.karafa.netAndroid "Private DNS", and the iPhone/iPad profile below. Port 853. This version is encrypted, so nobody on the network between you and the server can read or tamper with your lookups.
Prefer the encrypted one where you can

Plain DNS travels in the open — anyone operating the network you are on (a café, a hotel, your provider) can read every name you look up. DNS over TLS wraps it in encryption. If a device offers a hostname field rather than an IP field, that is the better option.

Set it up on your device

Choose your device below. The tab matching what you are reading this on is already selected. If you only do one of these, do the router — it covers everything in the house at once, including devices you cannot configure individually.

Check that it actually worked

Do not just assume it took effect. Two quick checks:

The eyeball test

Visit a news site that you know is heavy with adverts. Where banners used to be you should now see blank space or a small "cannot be reached" placeholder. That gap is the point — the advert was never fetched.

The exact test

On Windows open Command Prompt; on macOS or Linux open Terminal. Run this against a known advertising domain:

nslookup doubleclick.net

If filtering is active, the answer comes back as 0.0.0.0, as an empty result, or as "can't find". If you get a normal-looking public address instead, the change has not taken effect yet — reboot the device, or check that you edited the connection you are actually using rather than a different adapter.

Give it a moment

Devices cache old answers for anywhere between a few minutes and a day. If nothing seems different, restart the device — that clears the cache more reliably than waiting.

When a site breaks

Occasionally a filter list is too aggressive and blocks something you actually wanted — a payment page, a delivery tracker, a login button that does nothing. This is the one real downside of DNS filtering, and it is easy to diagnose.

SymptomWhat to do
A button does nothing, or part of a page is missing Likely a blocked domain. Send us the address of the page and we will allow the domain it needs — usually within a day.
No website loads at all The resolver is unreachable, or there is a typo in the address. Undo the change (below), confirm the internet works, then try again carefully.
Works on Wi-Fi, not on mobile data Expected if you configured the router only. Use Android Private DNS or the iOS profile to cover mobile data too.
A captive portal (hotel, airport Wi-Fi) will not open These hijack DNS by design, so encrypted DNS blocks them. Turn Private DNS off, sign in to the network, then turn it back on.

How to undo it

Nothing here is permanent, and you should know the way back before you start.

Any of these takes effect immediately — no reboot required, though clearing the cache does not hurt.

Common questions

Do I need a Karafa.net account for this?

No. The resolver is open to anyone. You do not need to tell us you are using it.

Will it slow my internet down?

A DNS lookup takes a few milliseconds, and there may be a very slight extra delay compared with your provider's server because ours is one location rather than dozens. In practice the blocked adverts save far more time than the lookup costs, so most people find pages load faster.

Will it break Netflix, banking or work systems?

It should not — filtering targets advertising and tracking domains, not services. Corporate VPNs are the exception: they often require their employer's internal DNS, so a work laptop may need this left alone or configured only for the home Wi-Fi profile.

What if your server goes down?

There is more resilience here than the single IP address suggests. The service runs on redundant resolvers, so one failing does not stop your lookups, and the whole rack sits behind a UPS — a battery large enough to ride out the local power cuts that occasionally hit the area, which has already been tested in practice more than once. It is also monitored continuously on the status page. It is still a small, self-run setup rather than a global company, so if you ever do want out, the undo section above takes half a minute.

Do you support DNS over HTTPS (DoH)?

Currently the encrypted endpoint is DNS over TLS on port 853, which is what Android and Apple devices use natively. If you specifically need DoH for a browser-level setting, email us and we will tell you where it stands.

Can it block adult content for a child's device?

The default lists cover ads, trackers and malware, not adult content. If you want a stricter profile for a specific household, ask — it is straightforward to arrange.