Invalid lan. and local. TLDs

John Horne john.horne at
Mon Aug 31 19:31:16 UTC 2009

On Sat, 2009-08-29 at 13:24 +1000, Mark Andrews wrote:
> Or one can just configure your recursive server as a stealth slave
> of the root zone.   You make a qery every hour or so and transfer
> it twice a day.
I have been wondering how to do a transfer twice a day without having to
write something (albeit it would probably be a simple shell script).

I have been running a root zone transfer on my home PC today by using:

      min-refresh-time 14400;       // 4 hours
      notify no;

This seems to work well enough, but for some reason it has done
transfers (or at least SOA checks) every 3 hours! I have run tcpdump on
the network interface to the F root server all day, and hence it shows
when the transfers have occurred.

So, two things:
1) is this a bug, setting min-refresh-time to 4 hours and it running
every 3 hours?
2) Is this a reasonable way to perform a root zone transfer twice a day?
(Using a value of 12 hours obviously.) Although we may not have right up
to the minute accuracy of the root zone, it would be at most 12 hours
out of date, and the DNS locally would still work since the TLD's have
multiple NS records (hence we wouldn't lose a TLD unless it had only one
NS and that was changed).


John Horne, University of Plymouth, UK
Tel: +44 (0)1752 587287    Fax: +44 (0)1752 587001

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