Using a DynDNS hostname in master-statement for a bind slave?

Mark Andrews marka at
Fri Jun 27 23:01:16 UTC 2014

In message <53ADB051.50407 at>, Doug Barton writes:
> On 06/27/2014 08:27 AM, Johannes Kastl wrote:
> > The slave server (HOST B) is reachable from the internet via a dynDNS
> > hostname.
> >
> > Now I want to setup another bind as slave on a server hosted at my
> > provider. It should use HOST B as its master, to transfer the zone and
> > act as a slave.
> >
> > BUT I found nothing in the documentation on how to deal with a master
> > server that has no fixed IP and is reachable via a dynamic hostname.
> That's because it cannot be done. You need a master with a fixed address.

Well its more that we havn't written the code to do it.  We actually
have the protocols to support nameservers being dynamically addressed
(other than the root servers).  UPDATE is capable of updating both
glue and actual records.  We lookup nameserver addresses for things
like NOTIFY.  There is nothing to stop a nameserver looking up
addresses for AXFR.  We already authenticate all these operations
using TSIG.

It's been on my personal TODO lists for over a decade now.

> If your zone content and IP address don't change often you could set a 
> very long expire time on the zone, and fix the master definition on your 
> provider's slave whenever it breaks, but that's pretty fragile.
> Good luck,
> Doug
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Mark Andrews, ISC
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