Working in the open: Enhancing privacy and security in the DNS

In 2018, we started pioneering work on securing one of the oldest parts of the Internet, one that had till then remained largely untouched by efforts to make the web safer and more private: the Domain Name System (DNS). We passed a key milestone in that endeavor last year, when we rolled out DNS-over-HTTPS (DoH) technology by default in the United States, thus improving privacy and security for millions of people. Given the transformative nature of this technology and in line with our mission commitment to transparency and collaboration, we have consistently sought to implement DoH thoughtfully and inclusively. Today we’re sharing our latest update on that continued effort.

Between November 2020 and January 2021 we ran a public comment period, to give the broader community who care about the DNS – including human rights defenders; technologists; and DNS service providers – the opportunity to provide recommendations for our future DoH work. Specifically, we canvassed input on our Trusted Recursive Resolver (TRR) policies, the set of privacy, security, and integrity commitments that DNS recursive resolvers must adhere to in order to be considered as default partner resolvers for Mozilla’s DoH roll-out.

We received rich feedback from stakeholders across the world, and we continue to reflect on how it can inform our future DoH work and our TRR policies. As we continue that reflection, we’re today publishing the input we received during the comment period – acting on a commitment to transparency that we made at the outset of the process. You can read the comments here.

During the comment period and prior, we received substantial input on the blocklist publication requirement of our TRR policies. This requirement means that resolvers in our TRR programme  must publicly release the list of domains that they block access to. This blocking could be the result of either legal requirements that the resolver is subject to, or because a user has explicitly consented to certain forms of DNS blocking. We are aware of the downsides associated with blocklist publication in certain contexts, and one of the primary reasons for undertaking our  comment period was to solicit constructive feedback and suggestions on how to best ensure meaningful transparency when DNS blocking takes place. Therefore, while we reflect on the input regarding our TRR policies and solutions for blocking transparency, we will relax this blocklist publication requirement. As such, current or prospective TRR partners will not be required to mandatorily publish DNS blocklists from here on out.

DoH is a transformative technology. It is relatively new and, as such, is of interest to a variety of stakeholders around the world. As we bring the privacy and security benefits of DoH to more Firefox users, we will continue our proactive engagement with internet service providers, civil society organisations, and everyone who cares about privacy and security in the internet ecosystem.

We look forward to this collaborative work. Stay tuned for more updates in the coming months.