topology hides nameserver?

[Mathias Koerber]

Hi All,

on one of our caching NSes, I had a funny problem with the topology statement:

I set it up to have my NS prefer the local secondary NSes in cases where a domain
is served by both our secondary NSes as well as foreign ones. 165.21.83/24 is
our internal auth NS that is located very near to this cache, so we prefer it most.

        topology {
                localhost;
                localnets;
                165.21.83/24;
                165.21/16;
                };

Now I had a case where queries for this domain

	idealsoft.com.sg.       1h48m11s IN NS  secdns.cyberway.com.sg.
	idealsoft.com.sg.       1h48m11s IN NS  pridns.idealsoft.com.sg.

	;; ADDITIONAL SECTION:
	secdns.cyberway.com.sg.  1D IN A  203.116.1.94
	pridns.idealsoft.com.sg.  8h1m5s IN A  165.21.128.217

simply timed out trying to obtain info from 165.21.128.217, when it was unreachable,
instead of falling back to 203.116.1.94.

Adding a 
	0.0.0.0/0 
at the end of the topology list cured that, but it's still
not clear to me why it refused querying the secondary nameserver. From the 
documentation, topology is supposed to only influence the preference, but does not
declare any other nameservers unusable..

This is on BIND-8.2.2-P5

Any help is appreciated.


Mathias Koerber	  | Tel: +65 / 471 9820    |   mathias at staff.singnet.com.sg
SingNet NOC	  | Fax: +65 / 475 3273    |            mathias at koerber.org
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