ITHI Metric M5, Recursive Resolver Integrity

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The M5 metrics measure the "integrity" with which resolvers process queries. The metric is computed by sending specially crafted queries at DNS resolvers from a large number of clients, including queries to domains under the experimenters' control. This allows us to analyze how recursive resolvers manage key part of the service, and how well responses sent to stub resolvers track data updates by the authoritative servers. There are two ways of measuring these metrics: either as a fraction of the user population; or, as a fraction of the total number of resolvers. We provide both evaluations based on estimation of the population size behind each of the resolvers that we track. We also provide an estimate of the fraction of the global population behind the 10000 largest resolvers.

There are five components in the M5 metric:

M5.1 to M5.5 only consider the individual resolvers identified by an individual IPv4 or IPv6 address, but for M5.6 we may group several addresses together if they belong to the same "resolver service". We also observe that clients may send their first queries to one resolver, but if it does not respond they may try other resolvers. Some clients send these first requests in parallel use multiple resolvers. For that reason, be use four different methods for computing concentration, leading to four different submetrics. The details of grouping and computation are explained in the "about M5" page.

The following table provides the value observed for the metrics in the current month, as well as the average value over the 3 previous months, and the "historical" minimum and maximum observed since the beginning of the measurements.

M5.1 (% alignment of cache time to SOA TTL) Current Value Past 3 months Historic Low Historic High
M5.1.1 (?) % of users using resolvers that re-fetch early - - - -
M5.1.2 (?) % of users using resolvers that re-fetch according to TTL - - - -
M5.1.3 (?) % of users using indeterminate resolvers - - - -
M5.1.4 (?) % of resolvers that re-fetch early - - - -
M5.1.5 (?) % of resolvers that re-fetch according to TTL - - - -
M5.1.6 (?) % of resolvers where cache time is indeterminate - - - -
M5.2 (% auto cache refresh) Current Value Past 3 months Historic Low Historic High
M5.2.1 (?) % of users using resolvers that auto-refresh their cache - - - -
M5.2.2 (?) % of query load due to cache refresh - - - -
M5.2.3 (?) % of resolvers that auto-refresh their cache - - - -
M5.3 (% EDNS0 DO query rate) Current Value Past 3 months Historic Low Historic High
M5.3.1 (?) % of users using resolvers that set the DO bit in queries - - - -
M5.3.2 (?) % of resolvers that set the DO bit in queries - - - -
M5.4 (%DNSSEC Validation rate) Current Value Past 3 months Historic Low Historic High
M5.4.1 (?) % of users using resolvers that perform DNSSEC validation - - - -
M5.4.2 (?) % of resolvers that perform DNSSEC validation - - - -
M5.5 (Distribution of resolver use) Current Value Past 3 months Historic Low Historic High
M5.5 (?) % of users using one of the top 10,000 resolvers - - - -
M5.6 (Concentration of the resolver services) Current Value Past 3 months Historic Low Historic High
M5.6.1 (?) Number of first use resolvers (subnet granularity) seen by 50% of users - - - -
M5.6.2 (?) Number of first use resolvers (subnet granularity) seen by 90% of users - - - -
M5.6.3 (?) Number of first use resolvers (subnet granularity) used by 50% of users - - - -
M5.6.4 (?) Number of first use resolvers (subnet granularity) used by 90% of users - - - -
M5.6.5 (?) Number of all use resolvers (subnet granularity) seen by 50% of users - - - -
M5.6.6 (?) Number of all use resolvers (subnet granularity) seen by 90% of users - - - -
M5.6.7 (?) Number of all use resolvers (subnet granularity) used by 50% of users - - - -
M5.6.8 (?) Number of all use resolvers (subnet granularity) used by 90% of users - - - -
M5.6.9 (?) Number of first use resolvers (AS granularity) seen by 50% of users - - - -
M5.6.10 (?) Number of first use resolvers (AS granularity) seen by 90% of users - - - -
M5.6.11 (?) Number of first use resolvers (AS granularity) used by 50% of users - - - -
M5.6.12 (?) Number of first use resolvers (AS granularity) used by 90% of users - - - -
M5.6.13 (?) Number of all use resolvers (AS granularity) seen by 50% of users - - - -
M5.6.14 (?) Number of all use resolvers (AS granularity) seen by 90% of users - - - -
M5.6.15 (?) Number of all use resolvers (AS granularity) used by 50% of users - - - -
M5.6.16 (?) Number of all use resolvers (AS granularity) used by 90% of users - - - -