Date: Fri, 5 Apr 2002 12:02:09 +1000 (EST) From: Andy Farkas <andyf@speednet.com.au> To: <Mark.Andrews@isc.org> Cc: <hawkeyd@visi.com>, stable at FreeBSD <freebsd-stable@FreeBSD.ORG> Subject: Re: named connections "in vain" Message-ID: <Pine.BSF.4.33.0204051127580.39553-100000@backup.af.speednet.com.au> In-Reply-To: <200204032204.g33M4Ax56644@drugs.dv.isc.org>
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On Thu, 4 Apr 2002 Mark.Andrews@isc.org wrote:
> > Apr 3 07:38:20 sheol /kernel: Connection attempt to UDP 192.168.16.2:2314 fr
> > om 192.168.16.2:53
> >
> > I can't figure out what named is trying to talk with.
>
> Named is replying to clients that have already given up waiting.
> These are most probably SERVFAILs saying that the nameserver has
> given up but they could also be late answers where the nameserver
> has had to work through several dead servers.
Named is replying to itself, not a client, ie. the host at 192.168.16.2
made a request to 192.168.16.2 which timed-out.
> > The only theory I can
> > come up with is that named is not waiting long enough for the forwarder to
> > reply, and does the query itself. When the forwarder does [finally] reply,
> > the connection has already been closed (either by named or ipf)?
I think it has something to do with the resolver library having a short
time-out value and named having a longer one.
An application (say sendmail) will use the resolver library to make a
query. The query goes to the nameserver listed in /etc/resolv.conf which
happens to be the same server as the app is running on. The query has a
short time-out - it fails because named hasn't answered yet - the app goes
on. Later, named gets an answer and tries to reply to a nonexistant
connection.
Do you know if in fact there are separate time-out values for the resolver
library and named?
--
:{ andyf@speednet.com.au
Andy Farkas
System Administrator
Speednet Communications
http://www.speednet.com.au/
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