Marketers have relied on third-party tracking cookies for the last 25 years to track consumer behavior online. Nearly all ad tech and martech platforms use cookies for targeting, retargeting, display advertising and behavioral marketing in general. Now, that’s all changing.

Today, Mozilla is flipping on the switch to turn on encrypted DNS over HTTPS for U.S. users by default. If you’re unfamiliar with the tech, the pitch is this feature will help prevent internet service providers from tracking the sites you go to.

DNS over HTTPS (DoH) is meant to address the inherent privacy vulnerabilities in how you surf the web. The Domain Name Service (DNS) is, in Mozilla’s words, “one of the oldest parts of internet architecture” and one that hasn’t seen a lot of changes in the past 30 years. This plays into tracking because when you go to a URL, your browser needs to look up the site’s corresponding IP address. It does that via the DNS. But, even if the site you’re visiting is encrypted via HTTPS, the DNS lookup is done over plain text. That means ISPs—or other entities—can, if they so choose, easily figure out what websites you’ve gone to and build up a profile of your browsing habits. DoH is meant to circumvent that by ensuring the DNS lookup is also encrypted. It won’t necessarily stop tracking wholesale, but it will make it more difficult.

Ready or not, the cookie crackdown is in full effect. The cumulative effect of Intelligent Tracking Prevention (ITP) on Safari, Enhanced Tracking Protection (ETP) on Firefox, and more granular third-party cookie blocking on Chrome are making measuring digital marketing activities increasingly difficult.

That’s not to say that it’s the end of measurement, but things are going to be different from now on. The reality is that marketers need to completely rethink how to use testing frameworks for measuring marketing value.

While it seems pretty scary right now, keep in mind that cookies are a 25-year-old technology and we’ll definitely find a way to move on. It’s going to be all about exploring new technologies, innovation, and striking a balance between profit and privacy choices to avoid another wave of consumer backlash. Taking advantage of first-party data that you get when people intentionally engage with your brand is the first step toward accomplishing this.