In a post yesterday to the Microsoft Tech Community blog, Microsoft Windows Core Networking team members Tommy Jensen, Ivan Pashov, and Gabriel Montenegro announced that Microsoft is planning to adopt support for encrypted Domain Name System queries in order to “close one of the last remaining plain-text domain name transmissions in common web traffic.”
That support will first take the form of integration with DNS over HTTPS (DoH), a standard proposed by the Internet Engineering Task Force and supported by Mozilla, Google, and Cloudflare, among others. “As a platform, Windows Core Networking seeks to enable users to use whatever protocols they need, so we’re open to having other options such as DNS over TLS (DoT) in the future,” wrote Jensen, Pashov, and Montenegro. “For now, we’re prioritizing DoH support as the most likely to provide immediate value to everyone. For example, DoH allows us to reuse our existing HTTPS infrastructure.”
But Microsoft is being careful about how it deploys this compatibility given the current political fight over DoH being waged by Internet service providers concerned that they’ll lose a lucrative source of customer behavior data.
ISPs give a number of reasons for their opposition to DoH. Since it prevents them from viewing plain-text DNS requests, it prevents filtering and blocking of some content—including, in the United Kingdom, the enforcement of content-filtering requirements placed on them by UK law. Because of its adoption of DoH as part of the Firefox Web browser, the UK’s Internet Services Providers Association named Mozilla an “Internet Villain.”
In the US, ISP lobbyists have pressed Congress to prevent Google from deploying DoH on Chrome on antitrust grounds. Part of that lobbying is based on claims that Google would, as a letter from Comcast to members of Congress put it, “centraliz[e] a majority of worldwide DNS data with Google” and “give one provider control of Internet traffic routing and vast amounts of new data about consumers and competitors.”