Mozilla announced the creation of a “use-application-dns.net” “Canary Domain” that could be configured within ISPs to disable Firefox’s default use of DNS over HTTPS. On 2019/09/21 Wes Hardaker created a RIPE Atlas measurement to study resolvers within ISPs that had been configured to return an NXDOMAIN response. This measurement is configured to have 1000 Atlas probes query for the use-application-dns.net name once a day.
The full description of methodology is on Wes’ ISI site, which should receive regular updates to the graph.
