Re: Resolver not always resolving hostnames

From: Hiroki Sato <hrs_at_FreeBSD.org>
Date: Fri, 27 Oct 2006 02:56:00 +0900 (JST)
"Jiawei Ye" <leafy7382_at_gmail.com> wrote
  in <c21e92e20610240824n7e94e4c1jf454697cab4120a9_at_mail.gmail.com>:

le> On 10/24/06, Hajimu UMEMOTO <ume_at_freebsd.org> wrote:
le> > leafy7382> This is much better. It would be great if this is commited.
le> >
le> > I've committed it into 7-CURRENT, and I'll MFC it into RELENG_6 after
le> > 3 days.
le> >
le> > The fix should help in certain case.  However, it seems doesn't help
le> > for nork-san's case.  He could reproduce it, and sent me his ktrace
le> > output.  As far as I can see his output, his local name server (BIND
le> > 9.3.2-P1) returned the response with no answer record.  As a result,
le> > his csup ended up with following error:
le> >
le> >         Name lookup failure for "cvsup.jp.freebsd.org": hostname nor
le> >         servname provided, or not known
le> >
le> > I suspect that the BIND9's named have some problem.
le> >
le> >        "Name lookup failure for "cvsup.jp.freebsd.org": hostname nor servname \
le> >         provided, or not known
le> >        "
le> > Sincerely,
le> >
le> > --
le> > Hajimu UMEMOTO _at_ Internet Mutual Aid Society Yokohama, Japan
le> You are correct, I just ran into that a few times in the last hour.
le> But it is a lot less frequent than before. I also run a local BIND9
le> for our company. I think some commits happening after between Sept 30
le> and Oct 15th caused it, because I did not see such symptom before late
le> Sept and I rebuilt my system around mid Oct.

 According to log files on my public cvsup server which is suffering
 from this problem, this happened on 22 September at least.  I have
 not looked into the source files closely yet, but is it possible that
 the 9.3.2-P1 patch has a bug that can return 0/0/0 with NOERROR
 answer packet?  I confirmed that behaviors of 4.x's resolver and
 6.x's against such a malformed packet are the same, so I think it is
 not likely a bug in the resolver.

--
| Hiroki SATO

Received on Thu Oct 26 2006 - 16:22:14 UTC

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