Why You Still Need A Tracker Blocker On iOS

Stay safe out there

Key Takeaways

  • Apple’s App Tracking Transparency isn’t as effective as it sounds.
  • A VPN-based firewall can block any app connection.
  • Make sure you vet your security tools before trusting them.
1Blocker screenshots on Mac, iPhone, iPad


Apple has made a big deal about iOS 14.5’s new App Tracking Transparency (ATT) feature, so why do you still need to run a tracker-blocking firewall app to protect yourself?

The problem is that ATT isn’t a block-all solution to trackers. If a user (you or I) opts out of being tracked by apps, then Apple disables its own built-in ad-tracking system, and requires developers to respect that decision and disable any other tracking software in their apps. What ATT doesn’t do is actually block those third-party trackers. For that, you need a third-party app—but you need to make sure you trust it.

“It’s not so much whether I trust their morals, it’s whether I trust their security,” [iOS app developer] Graham Bower told Lifewire via direct message. “Allowing a third party to proxy your traffic creates another point of vulnerability if they get hacked.

How IDFA Works

IDFA, or Apple's Identifier for Advertisers, is a random ID number assigned to every Apple device. This lets apps track your activity without actually getting your personal details, although there are ways to tie the two together.

Advertisers can use the IDFA to personalize ads. And by “personalize,” they mean “gather as much data about you as possible in order to make ads that you’re more likely to click on.” You have been able to disable the IDFA on your iPhone or iPad for years, but if you didn’t, any app could use it to track your device’s app and internet usage. Advertisers could build up a picture of which apps and sites you use.

“There's a huge amount of personal information and activity that's being collected about us consumers without our consent,” Matthew Paxton, founder of gaming site Hypernia, told Lifewire via email, “not to mention the number of people that are not actually aware of this fact.”

Guardian promotional image of iPhone and firewall app


The new ATT rules mean that developers have to explicitly request access to the IDFA. The rules also say that apps have to respect your choice, and also disable any other tracking that they are using. You’ve probably spotted the flaw already. Any app developer that secretly was tracking you in the past will likely continue, if possible. 

Apps from the same developer also still can track you across its other apps. Facebook can use data from Instagram, for example. 

Tracker Blockers

When you use the Safari web browser, you can make use of third-party “content blocker” apps, also known as ad blockers. These apps maintain lists of ad servers, trackers, and other annoyances, and communicate those lists to Safari, which uses them to block unwanted connections. It works great, but only in Safari. Apps, and in-app browsers, are not affected. 

A new class of apps has risen to deal with this. One is Guardian Firewall, which routes all internet connections from your device through a VPN, and blocks trackers that way. 

Secure Tunnel screenshots from Lockdown


Lockdown uses another approach. All blocking is done on your device. It still routes all data through a VPN, but that VPN runs on your iPhone or iPad, not on a remote server. Either way, you should do your research to check that your firewall software isn’t also tracking you. Both Guardian Firewall and Lockdown publish audits to help you check. 

Last week 1Blocker, the iOS and Mac content-blocker app for Safari, added a tracker blocker. The new feature is included in the existing subscription, and it works locally on your device, like Lockdown. 1Blocker updates its list of blocked connections live, so you can put the app into a slide-over panel on your iPad, for example, and watch to see if apps are tracking you in secret.

Some of these connections are legit, kinda. Lots of apps use analytics services to send usage stats back from your device. This lets them troubleshoot apps and figure out usage patterns. But, in the end, analytics are just trackers by another name. They may not be used for targeting ads, but they are still leaking your data.

Should You Run A Tracker Blocker?

Yes, probably. There are very few downsides to using a firewall app to block unwanted app connections, and the upsides are huge. First, it’s hard to overstate the importance of trusting blocker apps. Safari Content Blockers are safe, because all they do is provide Safari with a list of URLs to block. Firewall software, on the other hand, potentially has access to any data that passes through it.

There's a huge amount of personal information and activity that's being collected about us consumers without our consent.

But in return for this bit of research, you get a lot. Apps cannot connect to Facebook, Google Analytics or other trackers like that. Dodgy weather apps cannot share your location data because they cannot connect and upload it. And so on. If you care about your privacy, then you should at least check out the options. 

However, if you already use a VPN to connect to the internet, then you can’t use these blockers. That’s because iOS can only run one VPN at a time. If you have to use a VPN to connect to your work network while working from home, then you’re out of luck.

Apple’s ATT rules have shaken things up, but in the end they offer less protection than we need. Luckily, the solutions exist, and you should check them out.

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