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My experiences with Pi-hole (scribe.disroot.org)
submitted 2 months ago* (last edited 2 months ago) by duikbrilletje@scribe.disroot.org to c/privacy@lemmy.ml

Pi-hole has helped improve my "relationship" with Firefox, or better phrased with Firefox forks like LibreWolf and Tor browser. Cool thing with Pi-hole is that you can watch the query log and see what happened in the background while you were surfing the Internet. I learned that :

  • After removing the sponsored shortcuts in Firefox and putting your own shortcuts there Firefox will make connections each time you start the browser. So, if you would have icons on your quick start page in Firefox for let's say EFF, Lemmy, Mastodon, HackerNews, with each Firefox start up, it would query these sites. which I didn't like so much. Since then I've gone back to a complete blank start page, removing search and all those quick start icons, using just toolbar folders with bookmarks.

  • Pi-hole defaults to blocking telemetry for Firefox and Thunderbird.

  • Signal uses Google servers I saw via Pi-hole. I thought that they were using Amazon servers, but looking at Wikipedia for the history of Signal hosting I learned that Signal went back to Google for hosting.

  • Firefox push notification services are hosted on Google servers. LibreWolf removes a lot of Google things that Firefox has by default, but not the push parts. With Pi-hole it is very easy to block that.

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[-] ZeDoTelhado@lemmy.world 35 points 2 months ago

Pi hole is an amazing tool and gives a lot of insight on what is being queried and blocked against the block lists. Also, makes completely transparent on the entire network to have nasty things blocked. One thing I will mention to make the setup better: make sure on the firewall level you can have a rule that makes every request for a DNS to go through pi hole. Some devices will use a hard coded DNS instead of respecting the one on the network

[-] Turun@feddit.de 7 points 2 months ago

Dns over https is immune to that firewall method, right?

[-] lemmyvore@feddit.nl 4 points 2 months ago

Yes but I think OP is referring to plain DNS requests to a preferred server.

You can hijack port 53 and redirect them to your preferred server. Also acts as a method of hardening DNS for devices and apps that do not support encrypted DNS.

[-] ZeDoTelhado@lemmy.world 3 points 2 months ago

Forgot to mention the port but that's it. Notorious devices like smart TVs and consoles like to use the hard coded DNS method

[-] Turun@feddit.de 1 points 2 months ago* (last edited 2 months ago)

Some devices will use a hard coded DNS instead of respecting the one on the network

Right, and I am pointing out that non-cooperative devices still won't be blocked by pihole if they so desire.

[-] lemmyvore@feddit.nl 2 points 2 months ago

Only if they do encrypted DNS, and you can still block them, you just can't force them to use the DNS you want. Embedded devices tend to avoid encryption to cut down on hardware requirements, they typically even pull their updates over unencrypted connections. IoT is a crazy world. 😃

And may I point out that if you have embedded devices freely connecting to the Internet you have a lot bigger problems than the fact they use encrypted DNS. Hell you should be so lucky for them to use encrypted DNS, at least it would be secure.

[-] Chiro@lemm.ee 1 points 2 months ago

What would be an example of an embedded device?

[-] lemmyvore@feddit.nl 2 points 2 months ago

Media players, TVs, IP cameras, lightbulbs... anything with wifi capability really.

[-] Chiro@lemm.ee 1 points 2 months ago

Is there a safe way to use these devices? I’m moderately tech savvy at best, and I do worry a lot about my tv. I also use some smart plugs to manage equipment on my aquarium, but that’s it. I’ve considered the implications of these devices, but didn’t know if there was anything I could do about it.

[-] jjlinux@lemmy.ml 3 points 2 months ago

Who do you think developed DoH? Google has it's paws on everything. It may be private, but as soon as I see Google, I'm out of there.

[-] ZeDoTelhado@lemmy.world 3 points 2 months ago* (last edited 2 months ago)

I was making a quick check, and yes, the DoH situation is a bit more dicey. From how I see it, the best way to make this work is to, at the firewall level, either block as much as possible any requests that look like DoH (and hope whatever was using that falls back to regular DNS calls) or setup a local DoH server to resolve those queries (although I am not sure if it is possible to fully redirect those). In that sense, pihole can't really do much against DoH on its own

EDIT: decided to look a bit further on the router level, and for pfsense at least this is one way to do this recipe for DNS block and redirect

[-] Turun@feddit.de 5 points 2 months ago* (last edited 2 months ago)

Right, so flowing that link there are three ways for DNS:

Classic on port 53,

Dns over TLS on port 853

Dns over https.

The first two can be blocked, because they have specific ports exclusively assigned to them. DoH can't be blocked reliably, because it is encrypted and on a common port. Though blocking 443 on common DNS resolvers can force some clients to fall back to one of the variants that can be blocked/redirected

[-] Pete90@feddit.de 1 points 2 months ago

With most firewalls, there is an option to download ip lists for blocking. There are several list I don't recall right now, that aggregate DoH services. It's not perfect, but better than nothing.

[-] aStonedSanta@lemm.ee 2 points 2 months ago

What does something like this look like? I have an Orbi pro but have never really messed with firewall settings

[-] ZeDoTelhado@lemmy.world 3 points 2 months ago

Hm.... I am not familiar with that device myself, and since I use opnsense for a while I forget most people do not use routers outside of the provided one.

But in a theoretical sense, this firewall rule should look something like this:

  • origin of traffic is any IP that goes into port 53
  • outgoing traffic has to go to pi hole on port 53
[-] aStonedSanta@lemm.ee 3 points 2 months ago

Perfect thank you. My brain gets that. Had a long day of work working on IP centrex phones remotely with dumb end users.

[-] 1917isnow@lemmy.ml 10 points 2 months ago

Oh man glad you have learned about the favicons issue it's insane that we just accept such an easily fingerprintable method of getting TINY IMAGES. Is there a way to cache all of it? I just disable everything lol

[-] LWD@lemm.ee 6 points 2 months ago

After removing the sponsored shortcuts in Firefox...

with each Firefox start up, it would query these sites.

I don't like that. Sponsored sites get a free ping from FF?! I thought those icons would be preloaded.

[-] sabreW4K3@lazysoci.al 23 points 2 months ago

It's for the thumbnail/logo

[-] duikbrilletje@scribe.disroot.org 5 points 2 months ago

Yeah. I thought about that. When you add an icon to your rows of shortcuts in Firefox and it fails to fetch the correct icon and gives it a generic letter instead and you want to add an icon yourself you cannot just upload or insert an icon to your Firefox, you will need to point it to some web link where the remote icon is. I can imagine Firefox wants to check at each startup whether the remote icon has changed or not (Not completely unreasonable. Think about Twitter changing to X).

[-] lemmyvore@feddit.nl 3 points 2 months ago

Come on, who are we kidding. 😄 It's done for pings. The privacy implication is so in-your-face there's no way they missed it. 🙂

[-] bloodfart@lemmy.ml 4 points 2 months ago

Favicons are from 99. The technology and handling of them wasn’t developed to invade your privacy.

[-] lemmyvore@feddit.nl 2 points 2 months ago

We're talking about images on your homepage, which phone home every time you open the browser, and even each time you open a new tab.

You can't possibly believe that an organization that has been making a browser for a living for decades missed the implications of that.

[-] bloodfart@lemmy.ml 3 points 2 months ago

on my firefox those are all favicons. when you say that "they" phone home, what's happening is that the browser is requesting the favicon for the sponsored links so it shows the right mini logo above the name of the website. if you want to disable this behavior, you can simply disable sponsored links with the gear menu in the top right corner.

if you want to disable all favicons, disable browser.chrome.favicons (old?) and/or browser.chrome.site_icons and browser.shell.shortcutFavicons in about:config, clear your cache and restart.

i'm pretty sure that firefox pulls favicons from cache for favorites or recents or whatever, but i haven't checked.

[-] ReversalHatchery@beehaw.org 1 points 2 months ago

The OP has clearly said that the problem was not with the sponsored links, but with the links they added themselves. Also, with your response to disable favicons you dismiss the problem itself. The problem is that there are favicons, the problem is that they are reloaded/rechecked every single time unnecessarily. The solution would be for firefox to cache these icons if it doesn't do that already, to use this cache for loading the icons, and to heavily limit how often these icons are refreshed, with an option to never refresh them and maybe only refresh a single icon when refresh is pressed for it.
It would also be perfectly fine if refreshing it only happened on the next time the page is visited.

Sorry but your response reads like "your issue is silly, but if you really don't like how it works you can disable it in its entirety"

[-] bloodfart@lemmy.ml 1 points 2 months ago

That’s not a well thought out solution.

The problem you’re describing is that the sponsored links get resolved every time the new tab page is opened (ostensibly).

There’s a couple of ways this could be a problem: the most obvious way is if you the user use favicons to determine what underlying software is actually providing a service. Last time I used it it was called favicon hashing because you wouldn’t even physically look at the icon itself, just compare its hash to a list of other hashes to immediately know the attack surface you were looking at.

But that’s tangential and not really related to the new tab page.

The other way it’s a problem is for users, applies to cached favicons and was reported in 2021, websites would compare their locally cached favicons and know that you’d visited before or if you had been logged in before and bunch of other information. It was a big deal because even the then relatively new privacy badger couldn’t stop it. The “fix” was just to resolve favicons as needed every time instead of caching. The impact was minimal, they’re just little icons after all, and that’s where we are today!

So the “phone home” behavior was actually a fix for real in the wild privacy exploitation.

If my response came across as seeing the issue as silly (I read it again, and can’t see it, perfect lemmy post!), it’s possible that understanding leaked through. If you’re determined to view it in a negative light, consider though that I took the person at their word that it was a problem instead of explaining that it’s a fix for another problem that was widely reported and provided detailed instructions for how to disrupt that process.

[-] ReversalHatchery@beehaw.org 1 points 2 months ago

the most obvious way is if you the user use favicons to determine what underlying software is actually providing a service

Sorry, I don't understand this point.
The way I understand it is that the user looks for icons of services it knows, but not the exact icon but just something similar. The thing I don't understand is why is this a problem, but probably I misunderstood something.

The other way it’s a problem is for users, applies to cached favicons [...]

I see. I think caching could be solved in a way that does not reintroduce that tracking possibility, though.
One approach would be to only have that cache be used by the new tab page. Page visits always update it, but not read it.
Another would be to always use the cache, but never tell the server that we have that icon cached. The former is probably better though.

If my response came across as seeing the issue as silly

In hindsight probably I have misread something. Sorry for the tension.

[-] bloodfart@lemmy.ml 1 points 2 months ago

The first example I gave is a Classico way that a person would examine favicons to determine the software serving the website. If I wanted to do this to your website I’d resolve a bunch of your sites pages and look for a favicon that’s the default of like nginx or something then when I find it I know what I’m up against.

There’s not really a way to do caching that defeats the second example. The whole point of caching is to avoid sending a bunch of data back and forth, so even if you don’t let a website touch and grab all over the objects in the cache and instead only treat the page’s content as a manifest then the website will still be able to figure out what favicons corresponding to dates and times you’ve got in there by seeing weather or not the browser asks for them to be sent.

I guess you could just not say anything to the web server, let it send whatever it wants and ignore it, but at that point you’d be better off to do the default behavior of just not caching favicons instead and skip a step.

[-] ReversalHatchery@beehaw.org 2 points 2 months ago

then the website will still be able to figure out what favicons corresponding to dates and times you’ve got in there by seeing weather or not the browser asks for them to be sent.

But the idea is that the website can't tell that, because websites would use a different cache store than the new tab page.
Even if facebook's icon is saved in the new tab page's cache, when a website wants to load that icon it will only try to find it in the normal cache. If it's not there or it is expired, it is requested again, passed to the normal cache store, and the normal cache store can also give that to the cache store if the new tab page.

[-] ReversalHatchery@beehaw.org 1 points 2 months ago

The new tab page is not from 99, however. And even for generic favicon handling my experience in case if bookmarks is that the bookmark won't have the favicon of the website if it couldn't obtain in in the moment the bookmark was created. So no, it does not seem to be an issue with the favicon system itself, but rather the new tab page.

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[-] ichbinjasokreativ@lemmy.world 4 points 2 months ago

The icon thing can be worked around with something like heimdall. I host my own docker container of it and just set that as my startup page in my browser. Looks much nicer than a blank page and everything happens in my own network.

[-] mumblerfish@lemmy.world 3 points 2 months ago

How does pi-hole help with Tor Browser? Does DNS not go through the Tor network?

[-] duikbrilletje@scribe.disroot.org 5 points 2 months ago

You're right. My point was that Pi-hole made me appreciate the Firefox forks more because the plain Firefox is FULL of GOOGLE!

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[-] barbara@lemmy.ml 2 points 2 months ago

Ever since using comouters I wonder why it is not built in to monitor your queries.

[-] shortwavesurfer@monero.town 1 points 2 months ago

I haven't used it in quite a long time but not because it was bad but just because it only worked on my wifi and I didn't want to try to set up a VPN to get it to work on mobile but I found that Control D has a free ad block and malware block DNS that can be done with DNS over HTTPS and so that is what I use

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this post was submitted on 18 Apr 2024
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