Comcast's Xfinity Internet Service Joins Firefox's Trusted Recursive Resolver Program

Mozilla, the maker of Firefox, and Comcast have announced Comcast as the first Internet Service Provider (ISP) to provide Firefox users with private and secure encrypted Domain Name System (DNS) services through Mozilla´s Trusted Recursive Resolver (TRR) Program, the companies said.

For more than 35 years, DNS has served as a key mechanism for accessing sites and services on the Internet. Functioning as the Internet´s address book, DNS translates website names, like and, into the Internet addresses that a computer understands so that the browser can load the correct website.

Over the last few years, Mozilla, Comcast, and other industry stakeholders have been working to develop, standardize, and deploy a technology called DNS over HTTPS (DoH). DoH helps to protect browsing activity from interception, manipulation, and collection in the middle of the network by encrypting the DNS data.

Encrypting DNS data with DoH is the first step. A necessary second step is to require that the companies handling this data have appropriate rules in place — like the ones outlined in Mozilla´s TRR Program.

This program aims to standardize requirements in three areas: limiting data collection and retention from the resolver, ensuring transparency for any data retention that does occur, and limiting any potential use of the resolver to block access or modify content. By combining the technology, DoH, with strict operational requirements for those implementing it, participants take an important step toward improving user privacy.

Mozilla is the not-for-profit behind the popular web browser, Firefox. Visit for more information.

Comcast Corporation (Nasdaq: CMCSA) is a global media and technology company with three primary businesses: Comcast Cable, NBCUniversal, and Sky. Visit for more information.