[Kea-users] Suppress DDNS for reservations

Wed Mar 9 15:57:48 UTC 2022

While perhaps not ideal, if you have control over what the static 
clients send in their DHCP requests, having them send an FQDN option 
with the N-S flags to N=1, S=0 would tell the server to not do any 
updates.  See this section:

https://kea.readthedocs.io/en/latest/arm/dhcp4-srv.html#when-does-the-kea-dhcp4-server-generate-a-ddns-request


On 3/9/22 09:50, Frey, Rick E wrote:
>
> I first wondered if something could be done in a class but as you 
> mention, docs indicate that ddns-send-updates directive is limited to 
> subnet as lowest level so doesn’t look there is much options in 
> current Kea config.
>
> Other options:
>
>   * Have clients with host reservation set option 81 bits to disable
>     DDNS updates.
>   * Prevent DDNS updates on DNS server for specified zones/names.  
>     Not sure what nameserver you’re using but BIND can be configured
>     to prevent DDNS updates at individual name level if needed.
>
> *From: *Kea-users <kea-users-bounces at lists.isc.org> on behalf of 
> Francis Dupont <fdupont at isc.org>
> *Date: *Wednesday, March 9, 2022 at 5:05 AM
> *To: *Kenneth Porter <shiva at sewingwitch.com>
> *Cc: *Kea users <kea-users at lists.isc.org>
> *Subject: *Re: [Kea-users] Suppress DDNS for reservations
>
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>
> Kenneth Porter writes:
> > I've enabled DDNS for my subnet but I don't want it used for 
> reservations,
> > only for the pool. The DNS entries for reservations are manually 
> entered in
> > my DNS in a higher-level domain. (The pool is entered in the "dhcp"
> > subdomain which allows updates.)
> >
> > My subnet is a /16 and the pool is a specific /24 of that. Other 
> /24's are
> > used for specific functions, including the gateway. So I can't just 
> put the
> > pool in its own subnet or it will get the wrong mask and won't be 
> able to
> > reach the gateway.
> >
> > I can't use ddns-send-updates set to false in a reservation. It only 
> works
> > in a subnet declaration or at global scope.
> >
> > What am I missing?
>
> => I suggest to try a shared network with two subnets covering the same
> range but with different textual representations (e.g. put ...1 in the
> second).
>
> Thanks
>
> Francis Dupont <fdupont at isc.org>
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