Strang name resolution behavior

Dr. Harry Knitter harry at knitter-edv-beratung.de
Thu Apr 20 09:16:40 UTC 2006


Am Donnerstag, 20. April 2006 10:25 schrieb Stefan Puiu:
> On 4/19/06, Dr. Harry Knitter <harry at knitter-edv-beratung.de> wrote:
> > Am Mittwoch, 19. April 2006 15:56 schrieb Stefan Puiu:
> > > Could it be that the hosts in mydomain.local. that you want to use are
> > > also defined in /etc/hosts? Because in that case the nameserver would
> > > not be queried.
> > >
> > no. If I had it in hosts, ping would work .
> 
> Not if it would point to the wrong IP.

Really, this is not the first bind I have configured.
When I insert the entries in /etc/hosts everything is resolved perfectly. 
Without these entries the behaviour described can be noticed

> Also, you said that dig/host 
> work, but not normal programs, now the only differences I can think of
> are that 1) normal programs go through the resolver library, which
> will read /etc/hosts before doing an actual query (because of what you
> have in /etc/nsswitch.conf)

The normal behaviour would be in this case
first query /etc/hosts; if this fails; query bind

changing the sequence in nsswitch.conf would result in
first query bind; if this fails; query /etc/hosts

> and 2) the domain would be appended on all 
> non fully qualified queries (i.e. somehost as opposed to
> somehost.mydomain.local.).
> 
I tried that with FQDNs an short names: same thing because search 
<domain-name> entry exists in resolv.conf

> How does ping fail? 
unknown host <machine | CNAME>.mydomain.local

> Are you sure it doesn't get to query the 
> nameserver?
As already posted there are no entries in query log at all when pinging, the 
host commands are recorded.
If I try the same from a M$-client all queries are recorded in query log.

> Can you try tracing if there are any packets sent using 
> tcpdump? Or alternatively, use strace to see what actually happens
> when ping needs to resolve?
> 
> How are your applications failing? Are they timing out on all queries?

yes

> Do your Windows clients have a default domain defined, just like the
> Windows ones?

yes

Regards

Harry



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