On 12/11/2015 22:45, Stephane Bortzmeyer wrote: >>> For instance, probes 16659, 17072, 17620, 17854 use a resolver >>> which yields a REFUSED for any request and probe 19948, 20065 one >>> with systematic SERVFAIL. > ... >> The above probes are mostly tagged as "resolves-a[aaa]-correctly" >> because they managed to resolve certain A records (e.g. MSM ID >> 1698856). Can you provide the measurement ID(s) where you see the >> REFUSED and SERVFAIL responses? > > Probes 19948, 20065 now seems OK. But 16659, 17072, 17620, 17854 still > return REFUSED: measurements #2928193 and #2928199.
I think what is happening here is that all of those probes except for 17854 have at least *one* resolver which does respond to queries. 17854 seems to have no resolvers responding successfully, which is why it has the tag "Doesn't Resolve A". This is because the "Resolves A Correctly" tag is really "Resolves A Correctly (for at least one resolver) (for at least one pre-designated stable target)". We have discussed internally creating another set of tags which say something about the reliability and stability of DNS resolution, rather than our current liberal tags which basically claim something like "you will probably get *some* usable results from this probe". I would be interested to hear your (or anybody else's) thoughts on whether you would use such a reliable/stable DNS resolution tag, and what kind of criteria you would expect for it to be applied. Cheers, Chris
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