qtype=any messages are cached especially in bind9 resolver?
zhanglikun at cnnic.cn
Tue May 8 10:42:47 UTC 2012
When I dig at my bind9 resolver with qtype=ANY, I find the message never
expire and being refetched until the last rrset expire, if there are several
rrsets in answer section, when one rrset in answer section expires, the
query client will get one cached message just without the expired rrset.
It's different with unbound and google dns 188.8.131.52, which will refetch the
entire message from authoritative server when any rrset in answer section
You can do the same test with qname=cnnic.cn, cnnic.cn mx record's ttl is
But, Bind9 resolver will refetch the qtype!=ANY message which have cname and
other type records in answer section, when any rrset expires.
So my question is why bind9 do like that?
Software Department, CNNIC
Email: zhanglikun at cnnic.cn
MSN: kerryzhang1227 at hotmail.com
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