Understanding how queries are forwarded to backends
---------------------------------------------------
-Initially dnsdist tried to forward a query to the backend using the same protocol than the client used to contact dnsdist: queries received over UDP were forwarded over UDP, and the same for TCP. When incoming DNSCrypt and DNS over TLS support were added, the same logic was applied, so DoT queries are forwarded over TCP. For DNS over HTTPS, UDP was selected instead for performance reason, breaking with the existing logic.
+Initially dnsdist tried to forward a query to the backend using the same protocol that the client used to contact dnsdist: queries received over UDP were forwarded over UDP, and the same for TCP. When incoming DNSCrypt and DNS over TLS support were added, the same logic was applied, so DoT queries are forwarded over TCP. For DNS over HTTPS, UDP was selected instead for performance reason, breaking with the existing logic.
Before 1.7.0, which introduced TCP fallback, that meant that there was a potential issue with very large answers and DNS over HTTPS, requiring careful configuration of the path between dnsdist and the backend. More information about that is available in the :doc:`DNS over HTTPS section <guides/dns-over-https>`.