[Pdns-users] 3.4-rc1 with ddns, tsig and bind's allow-update-forwarding

Ruben d'Arco cyclops at prof-x.net
Tue Aug 26 07:36:57 UTC 2014

Hi Martin,

No worries. PDNS is not my work, just hobby so i have to squeeze it in between all kinds of stuff :-)

I am able to reproduce the issue locally now, which is already wonderful as that gives me options to debug it further.

When a update message is forwarded, the message ID is rewritten (as per rfc2136). I think PDNS validates the message with that new ID, and it might need to do it with the old ID. I still need to figure out what is correct here. The old ID is in the message somewhere together with the TSIG record. I need to try and implement a fix like that to validate if this really is the case. 

So, we're moving forward and i hope i can give you a patched PDNS later this week.


On Tue, Aug 26, 2014 at 03:57:31PM +0900, Martin Chandler wrote:
> Hi Ruben,
> Sorry to keep bothering you on this, but I notice that dhcpd sends
> the original update request via UDP, but bind forwards the request
> via TCP.
> Could it be that there is some difference in the way PDNS is
> handling TCP packets over UDP packets, and somehow mis-reading the
> data that BIND is sending?
> That would possible explain why setting the dhcp server to talk
> straight to PDNS works, because it would be sending the expected UDP
> packet, but forwarding over TCP fails.
> btw, I also tried setting up a CentOS 6.5 server:
> BIND 9.8.2
> DHCPD 4.1.1
> PDNS 3.4-rc1
> but get the same results (i.e. unsuccessful).
> Thanks,
> Martin

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