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Mozilla Testing DNS-over-HTTPS in Firefox

Mozilla is moving forward with yet another project designed to provide users with increased security: it is now testing DNS-over-HTTPS (DoH) in Firefox stable.

Only a small group of users will enjoy the feature for now, as it is still in the testing phase, but Mozilla is determined to work with industry players for a larger rollout. When that will happen, however, remains to be seen.

Mozilla has been already testing DoH in its browser, looking into the time it takes to get a response from Cloudflare’s DoH resolver. With the test results positive, revealing great performance improvements even for the slowest users, the Internet organization has decided to move forward with its plans. 

“A recent test in our Beta channel confirmed that DoH is fast and isn’t causing problems for our users. However, those tests only measure the DNS operation itself, which isn’t the whole story,” Mozilla’s Selena Deckelmann explains. 

Usually, Content Delivery Networks (CDNs) provide localized DNS responses, to send users to nearby hosts, for best performance. Cloudflare, however, uses a centralized resolver without EDNS Client Subnet, meaning that the process doesn’t work as well when using DoH with Firefox.

Because of that, the user might get less well-localized results, which would then slow the experience even if the resolver itself is accurate and fast. Mozilla says it can test this, and that they are studying the total time it takes to get a response from the resolver and fetch a web page. 

The organization is working with Akamai to understand the performance impact. Once a day, Firefox users enrolled in the study will fetch data from test web pages hosted by Akamai and featuring dummy content. Information on the time needed to look up DNS will be collected and sent to Firefox engineers for analysis. 

Mozilla is currently rolling out the feature to a small set of users in the Release channel in the United States and says Cloudflare’s DNS-over-HTTPS service will be used for the study. In-browser notifications about the experiment will also be provided, thus keeping users informed and allowing them to decline participation. 

“Moving forward, we are working to build a larger ecosystem of trusted DoH providers, and we hope to be able to experiment with other providers soon. We don’t yet have a date for the full release of this feature. We will give you a readout of the result of this test and will let you know our future plans at that time,” Deckelmann concludes. 

Related: Mozilla Brings Encrypted SNI to Firefox Nightly

Related: Cloudflare Encrypts SNI Across Its Network

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