DDNS, NOTIFY timeouts

[Mark Damrose]

"Reto Kortas" <reto.kortas at telekom.de> wrote in message
news:a39742$3l1 at pub3.rc.vix.com...
>
> Hallo everybody!
>
> I've some questions about DDNS and DHCP and they are all going around
> with timeouts!
>
> I'm running BIND9.2.0 and DHCP3.0rc6 on a linux box (SUSE 7.3) in our
> lab. I've setup one server
> acting as a primary dns master and another one is acting as a
> secondary together with DHCP3.0.
> The server performs DDNS updates and all is running well.
> But there are a couple of question which I'm not able to solve by
> reading manuals.
>
> 1. The DHCP server hands out an IP to a client and then attempts to
> update
>    the resource records(A, TXT, PTR)for this client on the master DNS
>    server. So, what happens if the master DNS is unreachable, for
>    example by some network problems in the LAN. Is there a counter or
> something
>    like that, after the DHCP tries again to update the DNS or would
> the DNS
>    update never be performed ???

I believe it would try again when the lease was next renewed, but that would
be a question to ask on the DHCP list.

>
> 2. Assumed the DNS update on the master has performed well, now the
> master DNS
>    has to inform his known slaves by a NOTIFY message about the
> changes. What
>    happens for example, if the master isn't able to reach a couple of
> slaves.
>    How would these slaves be able to hear about the changes so that
> they could
>    perform an IXFR.Send the master several NOTIFY messages until he
> receives an
>    acknowledge from all the slaves ???

No. The master sends out 1 NOTIFY.  The slaves would check the next time the
refresh timer expired.  The next time a DNS update took place, it would
generate another NOTIFY.

>
> 3. Afterwards, the slave has already received the NOTIFY, he would ask
> the
>    master DNS about what changes taken place. What happens if the
> slave could
>    reach the master so that he couldn't perform an IXFR. Did he try
> again and
>    again until he reached the master or did he stop.

It would try again at the retry interval.  If it continued to fail it would
stop serving the domain at the expire timer.

>
> thx to all
>
> Reto
>