Lobsters - 03 Oct 2026
System-level ad-blocking in Android in 2026
The Internet has become an advertising platform. Users of mobile devices are acutely aware of this, because mobile operating environments and apps force ads on their users, in addition to those that pollute the Web. It's getting harder to avoid the ads on Android handsets, as Android is increasingly locked down and difficult to customize. It's certainly not in Google's interest to make it easy to block ads.
It's still possible, though, to suppress most advertising, even in 2026.
This article is specifically about blocking ads at the system level, that is, in the Android platform itself, rather than in any particular app. Some Android apps, particularly web browsers, have their own methods of blocking ads, or can have such features added using third-party plug-ins. Oddly, though, the DuckDuckGo browser, whilst blocking the tracking that accompanies targeted advertising, doesn't specifically block ads - you need something more.
If you block ads at the system level, all apps - and the system itself - are protected. Moreover, methods for blocking ads can usually be extended to protect against trackers and other kinds of malware.
Basic principles
So far as I know, all system-level ad-blocking methods work by overriding DNS behaviour. DNS (domain name service) is the technology that maps hostnames to numeric IP addresses; a DNS lookup is the first step in almost all network operations.
Blocking ads using DNS amounts to finding the hostnames of know advertising services, and mapping them to bogus IP numbers. This can be done in the Android handset itself, or in some external DNS server.
Returning a bogus IP number doesn't prevent an app or browser trying to show advertising, or allow it to make better use of the screen space the ads take up. Apps vary in their responses to a failed attempt to display advertising - more on this later.
Blocking ads using DNS
There are essentially four methods to block ads using DNS changes.
- Use a commercial DNS service with ad-blocking features
- Use a commercial virtual private network (VPN) with ad-blocking features, like NordVPN
- Install an ad-blocking app that doesn't require root access.
- Use an ad-blocking method that requires root access, with or without a supporting app
Commercial ad-blocking DNS services
In general, when you make a connection to the Internet on an Android device, the DNS name resolution (mapping a hostname to a numerical Internet addresses) is performed by a server hosted by the handset's mobile carrier or Internet service provider.
Android allows you to override this behaviour, and select a custom DNS server that blocks ads. Well, it won't actually "block" anything - not really; the DNS server just returns a bogus IP number when your handset looks up the IP number that corresponds to the hostname of a known advertiser.
Depending on the DNS service you use you may, or may not, get some control over exactly what it blocks. Some users choose also to block access to pornography or on-line gambling, for example, for child protection.
How well these services work depends, of course, on how well the service's operators maintain their lists of known advertising hosts. Advertising services come and go, and even long-standing ones change their servers from time to time.
There are many commercial DNS services that support ad-blocking, and I don't endorse any in particular. Prices vary, and most services have a free trial. If you care about privacy, you'll want to use a service that keeps no logs, and you might want to use one that supports encrypted DNS. A rogue DNS operator might get access to sensitive data in all kinds of ways. It's possible, for example, for a DNS operator to direct requests for your on-line banking service to its own proxy, and slurp up your credentials when you log in. You should certainly be very careful and, while there are legitimate free DNS services, I'm rather suspicious of any service of this kind whose funding model is unclear.
Commercial VPNs with ad-blocking features
For many people this will be the simplest solution. If you subscribe to a VPN service for general privacy, blocking ads will often come at no extra cost. Ad-blocking VPNs typically redirect DNS lookups to their own servers, and return dummy IP numbers for known advertisers, just as a commercial DNS service does. VPNs therefore have all the same advantages and disadvantages as an ad-blocking DNS service. A big VPN operator will usually provide an Android app that configures the handset to use its servers, so set-up is pretty trivial for most people.
As with commercial DNS services, a rogue VPN operator can be very dangerous, and it's important to choose a provider carefully.
Non-rooted ad-blocking apps
So far as I know, all these apps exploit a loophole (of sorts) in Android's platform lock-down.
Like all Linux-based operating systems, Android provides a way for a device to override the DNS mappings of the Internet service provider it is using. There will be, somewhere on the handset, a file that contains a list of preferential name-to-IP mappings. On a non-rooted Android device, the user won't have permissions to change this file, so a simple method of blocking ads - maintaining a list of bogus DNS mappings for known advertisers in a file - is unavailable.
However, in a non-rooted device, you can install a VPN service. This has to be possible, if Android is to support VPNs at all. A non-rooted ad-blocking app will typically run a DNS server and a local (within the app) VPN host. The app will configure the handset to use its own VPN as the system VPN provider, which will make its own DNS server the system DNS. With control over DNS, the app can provide its own handling for name lookups, including those of know advertising servers.
Google, being an advertising company, isn't very keen on this kind of thing. It can't easily prevent the use of "local" VPNs without crippling VPN functionality completely but Google can, and does, make it difficult for non-technical users to get the appropriate apps. At present you can get apps like AdAway from alternative app stores like F-Droid.
Google is set on making this difficult, too, and before long you'll have to get the app's APK file from (hopefully) a reputable source, and jump through whatever hoops Google puts in the way of install software it doesn't like. At the time of writing, Google isn't making it impossible to install software from outside its Play Store, but it's getting more and more fiddly.
Most likely though, Google's obstructions won't ever be as difficult to surmount as rooting your Android handset and applying a definitive ad-blocking solution. Using an app like AdAway will probably continue to offer advantages over a commercial DNS or VPN service, even if Google makes it hard to install.
The most obvious advantage is that these apps are usually free to use. Despite this, a community of volunteer maintainers ensures that the apps' lists of known advertisers are as thorough as any provided by a commercial service. A disadvantage, though, is that all network traffic from all apps has to be routed through a single app on the handset. Not only does this create a network bottleneck, a rogue ad-blocker app is exactly as dangerous as a rogue VPN service. Fortunately, because these ad-blocking apps are usually open-source, there are limited opportunities for bad actors. I'd strongly advise against using one that isn't open-source, even if you don't plan on looking at the source code yourself.
Rooted ad-blocking approaches
If your handset is rooted, then ad-blocking is simple - in theory, at
least. Android's list of preferential name-to-IP mappings is in the file
/system/etc/hosts, so all you have to do is edit that file,
to direct advertisers' hostname to a bogus IP number. Usually the bogus
IP local address of the handset itself, 127.0.0.1. So
you'll have a hosts file full of entries like this:
127.0.0.1 08.185.87.0.liveadvert.com
127.0.0.1 08.185.87.00.liveadvert.com
...
The reason for using the handset's local IP number is that it must correspond to a system that the handset can actually reach. Otherwise, network access will be badly delayed as apps try to contact non-reachable advertising hosts. Of course, this means that every request for an advertising service will be directed back to the handset which, presumably, will reply with a error response to the app that makes the request. Since the request will fail immediately, this loopback network routing doesn't create an appreciable load on the handset.
This is all theoretically straightforward but, in practice, there are two major problems.
First, we need a source of hostnames to block. Lists of these are
widely available on websites, but the problem of maintenance is always
present. Some of these lists are truly vast and, without doubt,
reference hosts that no longer operate. If the hostname list is this
long, then all network access will be slowed, as the handset has to
parse the hosts file for each DNS lookup.
Probably the best source of ad-blocking hosts files is
the code of open-source ad-blocking apps like AdAway. This app can, in
fact, provide its list automatically when installed on a rooted handset,
which simplifies the set-up.
The second problem is that you can't just hack on the
hosts file, even as root - on all modern
Android devices it's on a read-only filesystem. So you'll need some
sofware that can manipulate the contents of the /system
directory during the boot process, while it's still writeable.
If you've rooted your handset, you almost certainly have a way to do
this already. If you're using Magisk, for example, you can use a module
to supply a new hosts file. Magisk modules live in
directories under /data/adb/modules, and any files in the
module's own system directory will overwrite the main
/system at boot time. So you can create a Magisk module
that provides its own /system/etc/hosts.
Happily, Magisk users don't have to do this manually, as the Magisk
developers have anticipated this usage. If you enable the "systemless
hosts" option in the Magisk app, it will create the necessary module
with all the necessary metadata in place. Thereafter, to create a custom
hosts file you just hack (as root) on
/data/adb/modules/root/system/etc/hosts, and then reboot.
Alternatively, you can use an app to make this change.
In fact, because this method of hacking on the hosts
file is so prevalent, ad-blocking apps like AdAway have built-in support
for it; but, of course, this support is only for rooted devices. If your
handset is already rooted, using a root-aware ad-blocking app is
probably the most effective way to manage ads. It's much faster than a
non-root app that installs a local mock VPN, and doesn't raise any of
the same security concerns. That's not to say there are no
concerns, and you should ideally check the hosts file such
an app installs, to ensure there are no mappings to anything except
127.0.0.1.
Limitations of ad-blocking methods
It's important to understand that no method of blocking ads is completely reliable, or has no side-effects.
Most notably, some Android apps simply won't work, or won't work properly, without their advertising. If you must use such apps, you'll need an ad-blocking method that allows you to customise the list of blocked sites. It won't be remotely obvious, just from the behaviour of the app itself, why it isn't working, or how to fix it. On a rooted handset you can track the network behaviour of a specific app in detail and, in theory, work out what it needs that you're blocking. In practice, it's easier to refer to the on-line discussions of such apps because, most likely, somebody else will already have done the work.
However, some apps go so far as to have all their ads built in; no ad blocker will stop such an app showing advertising, as there's no network operation to block.
It's also important to understand that Android caches DNS lookups in various places. Although some methods of ad-blocking allow the list of blocked hostnames to be configured on the fly, you might still have to reboot the handset to flush its caches.
Although it should be obvious, bear in mind that DNS-based ad-blocking only works where an app uses DNS. Since DNS-based ad-blocking is so commonplace, some app developers are implementing direct access to advertising servers using IP numbers, which renders all DNS-based approaches ineffective. This, fortunately, is still relatively rare.
Closing remarks
The ability to block ads at the system level is one of the few compelling reasons to root your Android handset in 2026. Blocking ads this way uses few, if any, additional system resources, and its effect extends to all apps.
If you can't root your device, or prefer not too, there are other ways to block ads, but none is as effective, as configurable, or as cheap.
Finally, if you mostly struggle with ads on websites, rather than in apps, the simplest approach might be to install a web browser with ad-blocking support, and avoid system-level ad-blocking entirely.
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Original: https://kevinboone.me/adblock.html