Get potentially validating resolvers

Get potentially validating resolvers.
Note, however, that only because a resolver queries for DS records (qtype 43) or DNSKEY records (qtype 48) and has the DO-bit set does not mean that it actually validates DNSSEC signatures.

select src, count(src) as tot
from dns.queries
where year = 2017 and month = 8
and (qtype = 43 or qtype = 48)
and edns_do = true
group by src
order by tot desc

2001:610:188:131:f816:3eff:fe35:1b0f 5520831
145.0.9.182 5518590
84.241.226.140 4673377
84.241.226.9 4632624
2a00:d78:0:106:94:198:154:24 3647013