I already know that private DNS is important for privacy. I'm using Quad9 btw.
But recently I hear a lot about NextDNS and similar providers that give more advanced features such as custom filters and domain blocking. I'm getting interested in that topic now as I have to use some proprietary apps with a lot of trackers in them.
However I'm really struggling to find useful information about what domains to block, what settings to use in one or another use case etc. I don't have much experience with firewalls and server stuff either which makes it even harder.
So, could anyone share some good resources on this so I can get started? Or should I just not worry about it and use a whole other system such as firewall?
Have a look at RethinkDNS, https://docs.rethinkdns.com/dns/ their wiki is pretty good. They have recommended block lists, and also have a feature that let's you search inside block lists to see what they actually cover.
If you are on Android they have a companion app, you do not need to use it though. The app adds a good firewall (capture and redirect port 53 for example) and detailed logs if you want. You can block domains and specific IP addresses.
I was recommended by a well-known privacy guide to use Rethink with AhaDNS Blitz, but it seems to fail often; nothing resolves until the VPN is stopped and restarted. Any ideas or advice?
With RethinkDNS I have had occasional failures on their Max resolver, changing to Sky then works. That has only happened two times though, and was fixed with a few hours.
Well, why don't you just try NextDNS? Don't like signing up to try a service? You don't have to. Go to nextdns.io, click "Try it now" and there you go. No account required for 7 days.
You don't need to add domains yourself, you just choose from existing blocklists they provide. Each have some description, just like all the settings.
I suggest ControlD.com p2 server as its free and kills known malware, trackers, and ads with no work other than adding it. They have a p3 that blocks big social and p0 blocks nothing.
I added ControlD p2 server for blocking ads, trackers, and malwRe to my familys' phones, my phone, and my router. The fact that it blocks known malware by default is a big selling point for me.
Been using Nexdns and is great . It adds the part of adblocking and maybe more agresive and granular filtering . Tried controlid but looks like a fancy version and less customized of it.
It is designed to generate blocking lists that can be used with unbound, the DNS resolver. There are even instructions for how to configure unbound so if you are new to it all you can follow along.
I use the resulting lists in my two local DNS name servers, running unbound.
The way it works is that if a query for a blocked address comes in to one of thenlocal DNS servers it returns a domain not found result. If the address is not on the block list then it forwards the query on to an internet DNS resolver securely using DoT.
You can gain further control over your DNS results by choosing those upstream resolvers carefully. Quad9 and Cloudflare etc all offer DoT resolving, along with some further filtering (eg. for malware), or completely unfiltered DNS if that's what you want.
Services like cleanbrowsing.org offer more fine grained filtering, useful if you want a family-friendly set of DNS results, based off categorify.org. You can pay for really fine tuned results, or there is a free layer which provides still very useful basic categories.
Combining the two forms of filtering, local advert and tracking blocking, along with open internet content categorisation, seems to be very effective.
I get complaints about too many adverts when my kids are on WiFi away from home. I take it as a compliment.