On Jan 28, 2026, at 18:22, Geoff Huston <[email protected]> wrote: > > If you assume that "DNS latency" is defined as the elapsed time between > passing a query to > a DNS resolver and receiving its response, and the "DNS latency" will vary > dramatically > depending on the state of the cache in the resolver(s) that are involved in > processing the > query, the query options (DNSSEC Enabled), the configuration of the queried > name > (Glue / no Glue records), the presence of a truncation flag in a UDP > response, and so on. > the number of zone cuts in the name, DNSSEC validation, and so on. > > This makes the measurement of "DNS latency" to be so extremely variable that > the concept > becomes somewhat meaningless, particularly when you might want to use such > measurements > as a comparator.
+1 to everything above. Note that this also affects the definition of "query latency": the latency for a query from a stub resolver to a recursive (with the RD bit set to 1) will likely be very different than the latency from a recursive resolver to an authoritative server (with the RD bit set to 0). If you want to try to define latency in the DNS, you have to specify what types of queries are being sent. --Paul Hoffman _______________________________________________ DNSOP mailing list -- [email protected] To unsubscribe send an email to [email protected]
