Caching server, forwarder list, dns failure

[Jean-Robert.Huon at alcatel.fr]

Hello,

I looked in FAQ and archives, but I could not find any answer to my
problem.

We are running a caching only server with a "forwaders @ip-dns1
@ip-dns2" line in the Named.boot file.

@ip-dns1 and @ip-dns2 are the addresses of 2 DNS acting as main/backup
servers.

Everything is running well except when the "main" dns (e.g @ip-dns1)
fails.

When this failure occurs, and when a new name resolution is asked, Named
tries normally the @ip-dns1 dns but seems to be "sticked" forever with
it before to decide that this dns shall be down and that it has to try
with @ip-dns2.

I would be very interested to know if the behavior of Named upon such a
failure is configurable in order that it decides to check the next dns
in the forwarders list after a couple of seconds (time limit).

Thanks in advance for any help

regards 

Jean-Robert