[Dnsmasq-discuss] Caching issue question
Nick
nick at double-stroke.com
Fri May 18 09:14:28 BST 2012
Hi,
I have a question to the caching of dnsmasq. I installed dnsmasq on
some of our boxes and configured the boxes to use 127.0.0.1 in
/etc/resolv.conf (so they use dnsmasq). That works really well and I can
resolve DNS queries on those boxes. All the queries get send from
dnsmasq to our internal DNS server (which has internal zones
configured). For testing I checked the incoming DNS requests on the
central DNS server with the usage of "dnscap". I encountered a strange
thing:
When I do a "dig session-storage.fd.corp" (fd.corp is an internal
domain) the first time on one box where dnsmasq is installed I can see
that one requests comes in on the central DNS server. The second time I
execute it, nothing comes in on the central DNS. So it gets cached in
dnsmasq which is fine. The problem appears when I do a "dig
session-storage.fd.corp" and a "dig AAAA session-storage.fd.corp"
alternately. I can see an incoming request for every dig request on the
central DNS server which means that there is no caching. I enabled
logging in dnsmasq and it seems that a request to the AAAA address
overwrites the cache entry for the A request. There is no AAAA entry on
our DNS server for session-storage.fd.corp (only an "A" entry is there
and this is a CNAME).
So my question is if this is a normal behaviour of dnsmasq or a bug? I
have a php application which requests those A and AAAA names alternately
(this is how I recognized it).
I am running dnsmasq 2.59 (the version from Ubuntu 12.04). Our central
DNS server uses powerdns.
Thanks for your help in advance.
Best Regards
Nick
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