[Dnsmasq-discuss] Insecure DS reply received, do upstream DNS servers support DNSSEC?
tore at fud.no
Sat Aug 24 18:47:32 BST 2019
Some more information:
> When the bug occurs, the error «Insecure DS reply received, do upstream DNS servers support DNSSEC?» is logged.
I think that the problem might be caused by this query in frames 7-8 of the PCAP:
7 0.007426 192.168.1.155 → 22.214.171.124 DNS 81 Standard query 0x56e3 DS google.com OPT
8 0.009033 126.96.36.199 → 192.168.1.155 DNS 639 Standard query response 0x56e3 DS google.com SOA a.gtld-servers.net NSEC3 RRSIG NSEC3 RRSIG OPT
There is no RRSIG record included that covers the SOA record (only the two NSEC3 records)
Occasionally (less than 5% of the time) my ISP's DNS server *does* include a RRSIG for the SOA record, though:
194 31.307161 192.168.1.155 → 188.8.131.52 DNS 83 Standard query 0x8ade DS google.com OPT
195 31.309053 184.108.40.206 → 192.168.1.155 DNS 804 Standard query response 0x8ade DS google.com SOA a.gtld-servers.net RRSIG NSEC3 RRSIG NSEC3 RRSIG OPT
When it does, Dnsmasq is able to answer the query successfully with the correct Insecure verdict (and cache it).
So the question then becomes: why does Dnsmasq require this RRSIG record, when other validating resolvers apparently do not?
> I have also observed the issue occurring while using public DNS servers like 220.127.116.11 instead of 18.104.22.168.
I now believe this was an unrelated problem, cf. https://mobile.twitter.com/toreanderson/status/1165225237115543554
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