[Pdns-users] serveral ALIAS questions

Klaus Darilion klaus.mailinglists at pernau.at
Mon Jun 11 10:53:45 UTC 2018


We soon put ALIAS into production. Hence, I have some questions to
better understand what's going on internally in PDNS.

a) What happens if the backend query (from PDNS-auth to resolver) is
unanswered? Will PDNS timeout the outstanding query or will it be kept
on the list for ever? If it times out - will PDNS send any responses?

I stopped the resolver and sent a query to an ALIAS RR. My obervation
is, that PDNS did send an upstream query, but it:
 - does not resend to the resolver
 - does not send any response (eg SERVFAIL) upstream

Hence I supsect that such unanswered backend queries will resist in some
queue forever.

Can you please comment an what really happens if the resolver is not

b) AFAIS the backend query supports only UDP without EDNS0. Hence, only
resposnes up to 512 bytes. Correct?

c) AFAIS queries to ALIAS RRs are not cached in the packet cache. Why not?


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