Date: Mon, 1 May 2006 20:46:40 +0200 From: Jan Gyselinck <freebsd-stable@b0rken.net> To: stable@freebsd.org Subject: resolver behaviour regarding searchlist and A/AAAA query replies Message-ID: <20060501204640.B8351@fire.b0rken.net>
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Hi, 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, I've not verified this on any other version yet. The queries I see are these: 22:15:29.657232 IP 172.16.21.2.57672 > 172.16.1.22.53: 54355+ A? images.slashdot.org. (37) 22:15:29.658189 IP 172.16.21.2.64080 > 172.16.1.22.53: 46066+ AAAA? images.slashdot.org. (37) 22:15:29.659407 IP 172.16.1.22.53 > 172.16.21.2.57672: 54355 1/13/1 A 66.35.250.55 (280) 22:15:29.659674 IP 172.16.1.22.53 > 172.16.21.2.64080: 46066 0/1/0 (96) 22:15:29.660514 IP 172.16.21.2.55636 > 172.16.1.22.53: 46067+ AAAA? images.slashdot.org.b0rken.net. (48) 22:15:29.661438 IP 172.16.1.22.53 > 172.16.21.2.55636: 46067 NXDomain* 0/1/0 (99) 22:15:29.661847 IP 172.16.21.2.58524 > 172.16.1.22.53: 46068+ AAAA? images.slashdot.org.bureau.b0rken.net. (55) 22:15:29.662720 IP 172.16.1.22.53 > 172.16.21.2.58524: 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? Regards Jan Gyselinck
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