DDNS fails. record allready exists

magic-bind at damage.devloop.de magic-bind at damage.devloop.de
Wed Dec 22 20:06:06 UTC 2010

keep calm ;-) I do not await a solution in 5 minutes ;-)

Am Dienstag, 21. Dezember 2010, 23:38:13 schrieb Bill Larson:
> On Mon, Dec 20, 2010 at 1:34 PM, <magic-bind at damage.devloop.de> wrote:
> > Hi List,
> > I have not yet found a solution for my problem. So I came here:
> > 
> > I use DDNS. Every night my server (in my local network) is shutting down.
> > On
> > the next day I have the problem that DDNS is no longer working, because
> > on update I get the error that the DNS record allready exists. What is
> > the solution?
> > 
> > I use BIND version 9.7.2_p3-r1.
> Well, there have been two questions asked but no more information given.
> That doesn't make it easy for anyone to help you.
> Some questions:
> 1. What is your DHCP server?  H/W and S/W.  Are you talking about a Linux
> box running "dhcpd" or a NetGear router running their DHCP server.  This
> may make just a little difference.

I use the DHCPD from http://www.isc.org/products/DHCP. I run Gentoo Linux on 
that server. This server is the router, dhcp server and dns server in my LAN. 
It is standard x86 hardware.

> 2. Why is your server shutting down?  Is this shutdown expected?  Also,
> which server are you referring to?  Is this the DNS server or the DHCP
> server (or both)?  You may have problems well outside the issue of DHCP and
> DNS.

It is shutting down every night, because I sleep at night ;-) DHCP and Bind 
both are running on this server. It is just an idea of me that bind is dumping 
the journal to the zonefile on shutting down. In primary zone file I have:

coffee                  A

But I never was writing it there by my own. This must be a result of DDNS.

> 3. Who is trying to perform the DDNS updates?  Is this the client machines
> or the DHCP server?

The DHCP tries to perform a DDNS update if the client sends its hostname (what 
it normaly should do). The client itselfs just performs a DHCP request. The 
DDNS update is done via rndc-key.

> 4. What do you see in your logs?  This may answer your question without any
> more work on anybody's part.

22-Dec-2010 20:35:44.451 update: info: client updating 
zone 'sugarland.local/IN': update unsuccessful: coffee.sugarland.local/A: 
'rrset does not exist' prerequisite not satisfied (YXRRSET)

I was reading that this means that the name/ip already exists. I was confused 
by the message but I found a page which explained why it says "not exist".

As I get the error message "coffee" had a record for But coffee 
was getting BTW: coffee is a notebook in dual boot between 
windows and linux. May this is part of the problem?!

> 5. What is your DNS server configuration?  Who is allowed to perform DDNS
> updates?

include "/etc/bind/rndc.key";
controls {
        inet port 953 allow {; ::1/128; } keys { "rndc-
key"; };

zone "sugarland.local" IN {
        type master;
        file "pri/sugarland.zone";
        allow-update { key rndc-key; };

zone "11.168.192.in-addr.arpa" IN {
        type master;
        file "pri/11.168.192.zone";
        allow-update { key rndc-key; };

> 6. When you say that "the DNS record already exists", have you confirmed
> this?  Just query your DNS server for that record and see if it is really
> there.  If it is not, this this message, which I am assuming is from your
> DHCP server or from your client machine, isn't true.  Then again, if it
> really does exist, why would you think that it magically disappears?  If
> you add a record to a zone, why would you think that it shouldn't still be
> there?

It is true. See above.

> 7.  You say you are running "BIND version 9.7.2_p3-r1".  Sorry, I can
> understand the 9.7.2-P3 part, but what is the "r1" you are referring to?
> (I'll bet you are running Gentoo Linux, but this is just an assumption.) 
> Is this built from the BIND sources from ISC or is this some package that
> you got from someone else?

You have win :-) This is a version extension from Gentoo. The package uses the 
sources from ftp://ftp.isc.org/isc/bind9. No patches are applied.

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