bind resolver, a/aaaa queries and searchlist behavior

Jan Gyselinck bind-users at
Fri Apr 28 19:49:44 UTC 2006


I was debugging some connection lag and I encountered some query
behavior which seems unnecessairy in my eyes.  The system in 
question is running one of the FreeBSD 6.1 prereleases, but since
it uses the bind resolver code I guess this behavoir is not
FreeBSD specific.

The queries I see are these:

22:15:29.657232 IP >  54355+ A? (37)
22:15:29.658189 IP >  46066+ AAAA? (37)
22:15:29.659407 IP >  54355 1/13/1 A (280)
22:15:29.659674 IP >  46066 0/1/0 (96)
22:15:29.660514 IP >  46067+ AAAA? (48)
22:15:29.661438 IP >  46067 NXDomain* 0/1/0 (99)
22:15:29.661847 IP >  46068+ AAAA? (55)
22:15:29.662720 IP >  46068 NXDomain* 0/1/0 (106)

So it sends out A and AAAA queries, so far so good.  It gets an answer
for the A record query, however the AAAA query retuns an empty answer.  
What I find strange though, is the fact it's now applying the searchlist
to get an answer on the AAAA query.  Other than the fact this could
potentially give unpredictable results in specific situations, I find
this rather illogical.  Since one of the queries (A or AAAA) succeeded
we _know_ the host in question exists (and the searchlist is there to
make non-fqdn queries work for 'local' hosts, by applying the searchlist
if the host does not seem to exist).  So, in short, isn't this a bug?


Jan Gyselinck

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