I second Jon.  Try 'dig <your-server-name>' 

At the bottom of the output will be the DNS server that responded.  I also 
don't know of any other caches that might cache this information other 
than the ones already mentioned.

Another thing you can try to "strace nslookup <your-server-name>".  This 
should also indicated how the resolver was called.  It should open 
/etc/resolv.conf, then open a socket to the nameserver to get the 
information.  If it does anything else, well, that's your answer.

Ken



On Fri, 30 Dec 2005, Jon Peatfield wrote:

> On Thu, 29 Dec 2005, Luke Scharf wrote:
> 
> > I've run into this problem before: how do I empty the DNS cache in Linux?
> >
> > I've changed a record in my DNS server, and ping still insists that the
> > server is at the old address.   However, if I point nslookup directly at
> > any/all of the DNS servers, I get the correct (new) address.
> >
> > I've tried touch'ing /etc/resolv.conf and /etc/nsswitch.conf.  I've
> > poked around in /var looking for the file that the DNS client uses to
> > store the database.  It has to be a file, because the last time I ran
> > into this problem, a reboot wouldn't encourage ping or any of the other
> > tools I tried to actually query the server and get the new record...
> >
> > Any suggestions?
> 
> I know of only 2 caches which might be relevant, nscd (as mentioned 
> before), and a caching named.  You can flush the nscd hosts table by 
> running (obviously as root):
> 
>    nscd --invalidate=hosts
> 
> you can see if there are things cached in there by running:
> 
>    nscd --statistic
> 
> The other is if you are running a local (cache-only) named, but you would 
> know that from the resolv.conf entries (e.g. a 127.0.0.1 or similar 
> nameserver entry).
> 
> If there is one you can cause it to reload/restart to flush the cache.
> 
> I'm assuming that you don't have any other sources of hostnames defined in 
> nsswitch.conf ...
> 
> On this host what does host/dig say for the DNS name you changed?
> 
>