DHCPv6 and DDNS

[Nicolas C.]

Le 18/06/2015 18:35, Philippe Clérié a écrit :
> Hello,
>
> First time on the list, mostly because I have not found my answer on
> Debian users or anywhere else.
>
> For the past couple of weeks I've been trying to set up isc-dhcp-server
> ( 4.3.1 ) on Debian Jessie for IPv6. I am at a point where the server is
> providing addresses but I cannot get it to update the DNS server.
>
> Both servers are on the same machine. The DNS server is bind9 ( 9.9.5 )
> and is working correctly for both IPv4 and IPv6. DHCPv4 is updating DNS
> with no problems and I can manage IPv6 addresses using nsupdate.
>
> The last change I attempted in my dhcpd6.conf was to set
> ddns-update-style to "standard" instead of "interim" as suggested by ISC
> (https://deepthought.isc.org/article/AA-01091/0/ISC-DHCP-support-for-Standard-DDNS.html).
> Setting update-optimization to false is also recommended.
>
> Note that interim style does not work either. In fact, the only time I
> saw some traffic from the DHCP transaction was just after changing to
> standard style. There was a bunch of denied DNS queries from the
> link-local address of the DHCP client. I allowed queries from fe80::/10
> to the DNS servers and thoses messages disappeared.

Hello Philippe,

Maybe the problem isn't on the servers sides. Keep in mind that, in 
order to work, the CLIENT has to use the same identifier for DHCPv4 and 
DHCPv6 transactions (RFC 4361).

That means that the client must run a recent version of ISC-DHCP and the 
DHCPv6 and DHCPv4 should be configured to both use the DUID has identifier.

This is not a problem for the DHCPv6 client but using the DUID instead 
of the client-identifier on DHCPv4 may require some tweaking on the 
client OS.

If you understand French, I wrote an article and did a presentation on 
this topic :

https://conf-ng.jres.org/2013/planning.html#article_27

Nicolas C.