[Dnsmasq-discuss] Caching issue question

Nick nick at double-stroke.com
Fri May 18 09:14:28 BST 2012

I have a question to the caching of dnsmasq. I installed dnsmasq on 
some of our boxes and configured the boxes to use 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 

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

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