Google this week announced the rollout of DNS-over-HTTP/3 (DoH3) for Android 11 and newer devices.
An encrypted DNS protocol, DoH3 is expected to provide performance and safety improvements compared to alternatives, mainly through the QUIC transport layer network protocol.
By default, even for encrypted connections, DNS lookups are not private – the base DNS protocol does not have encryption – something that has been resolved through solutions such as DNS-over-TLS (DoT) and DNS-over-HTTPS (DoH).
Support for DoT was introduced in Android 9, but Google says that the protocol incurs overhead on any DNS request. Although it enjoys wide adoption and has already been deployed by numerous public DNS operators, DoH doesn’t reduce overhead, the internet giant says.
DoH3, which should provide both performance and safety improvements courtesy of its use of QUIC, has been rolled out as part of a Google Play system update and will replace the use of DoT for well-known DNS servers that already support it.
“Which DNS service you are using is unaffected by this change; only the transport will be upgraded. In the future, we aim to support DDR which will allow us to dynamically select the correct configuration for any server. This feature should decrease the performance impact of encrypted DNS,” Google says.
Google also notes that the QUIC transport can resume a suspended connection, which is useful when the mobile device changes networks, and that DoH3 may outperform traditional DNS in unreliable networks.
“Field measurements during the initial limited rollout of this feature show that DoH3 significantly improves on DoT’s performance. For successful queries, our studies showed that replacing DoT with DoH3 reduces median query time by 24%, and 95th percentile query time by 44%,” the internet giant says.
DoH3 in Android, the company adds, also takes advantage of the Rust programming language that Android supports, which helps reduce the risk of security vulnerabilities.
Google also explains that Android will query a Cloudflare HTTP/3 library called quiche, which has “a memory-safe implementation, few dependencies, and a small code size.”
“With the introduction of Rust, we are able to improve both security and the performance at the same time. Likewise, QUIC allows us to improve network performance and privacy simultaneously. Finally, Mainline ensures that such improvements are able to make their way to more Android users sooner,” the internet giant says.