[FC3] Sites 'disappearing' from DNS

[Jean Francois Martinez]

What could be happenning is that your ISP is rotating his machines on
DNS and sending your notifications through DHCP.  But you have a static
configuration for named so it is pointing at machines who for some
reason don't have up to date data.  You have to read the DHCP
documentation in order for it updating your named config, and, very 
important, firewall config and then restarting both.


On Mon, 2005-04-04 at 13:47 +0100, Nigel Wade wrote:
> Brian Fahrlander wrote:
> > On Sun, 2005-04-03 at 14:43 -0700, Craig White wrote:
> > 
> > 
> >>the fact that it doesn't find it the first time but does on subsequent
> >>tries suggest that you have some problem with the setup and latency so
> >>your client times out before the dns lookup completes.
> >>
> >>Probably the best way to fix that is to fix your caching dns server.
> > 
> > 
> >     Well, if I had to get it twice to actually make it, sure...the funny
> > thing is, if I go there first with 'host' and find it, then use Firefox,
> > it still doesn't. (Denying all reason that *I* know)  Firefox just won't
> > find it. That's what makes me think Firefox is involved.   These are
> > sites I've visited every day or so for years...and I've not changed the
> > local /etc/resolv.conf or anything on my end for about as long.
> > 
> >     How can this be?
> > 
> 
> I would start by looking at nscd. It's responsible for caching all sorts of 
> info on the client and quite often gets itself very confused.
> 
> The 'host' command queries DNS directly without referring to nscd, whereas 
> the resolver library will use nscd if its running. If your DNS server fails 
> to resolve an entry this failure is cached by nscd (by default for 300s). 
> So, a 'host' command might return a valid response whereas any attempt to 
> contact it via the resolver/nscd would fail.
> 
> Next time this happens, try flushing the nscd hosts cache:
> 
> # nscd -i hosts
> 
> and try again.
> 
> -- 
> Nigel Wade, System Administrator, Space Plasma Physics Group,
>              University of Leicester, Leicester, LE1 7RH, UK
> E-mail :    nmw at ion.le.ac.uk
> Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555
> 
-- 
Jean Francois Martinez <jfm512 at free.fr>