What does update-conflict-detection true; do

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What does update-conflict-detection true; do

thomas.zenz@oenb.at
Hi

I didn't find an official description for it. Only:

If update-conflict-detection is true, the dhcp-server updates the dns-server with the A, PTR and TXT record.
If update-conflict-detection is false, the dhcp-server updates the dns-server with only the A and PTR record.

Is that all?
It sounds more like ignoring DHCID or not overwriting entries w/o DHCID.

Ing. Thomas Zenz
IT-Operations

Oesterreichische Nationalbank
Garnisongasse 15, 1090 Wien
T:+43(0)1 40420-2744
F:+43(0)1 40420 04-2744
M: +43(0)664 1426188
[hidden email]
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Re: What does update-conflict-detection true; do

Nicolas C.
Le 18/07/2017 à 14:19, Zenz, Thomas a écrit :
> Hi
>
> I didn't find an official description for it. Only:
>
> If update-conflict-detection is true, the dhcp-server updates the dns-server with the A, PTR and TXT record.
> If update-conflict-detection is false, the dhcp-server updates the dns-server with only the A and PTR record.
>
> Is that all?
> It sounds more like ignoring DHCID or not overwriting entries w/o DHCID.

That's all but if you disable it, it means that basically any host can
overwrite any record and multiple hosts with the same name will
continuously take turn to update the same record.

With "update-conflict-detection" on, the first host get to update the
zone and after that any other hosts with the same name are rejected as
long as the lease of the first one is valid.
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Re: What does update-conflict-detection true; do

Glenn Satchell
In reply to this post by thomas.zenz@oenb.at
man dhcpd.conf

          The update-conflict-detection statement

            update-conflict-detection flag;

            If the update-conflict-detection parameter is true, the server
will perform standard DHCID multiple-client, one-name conflict
detection.  If the parameter has been set false, the server
will skip this check and instead simply tear down any previous
bindings to install the new binding without question.  The
default is true.

So false means ignore the DHCID record.

regards,
-glenn

On Tue, July 18, 2017 10:19 pm, Zenz, Thomas wrote:

> Hi
>
> I didn't find an official description for it. Only:
>
> If update-conflict-detection is true, the dhcp-server updates the
> dns-server with the A, PTR and TXT record.
> If update-conflict-detection is false, the dhcp-server updates the
> dns-server with only the A and PTR record.
>
> Is that all?
> It sounds more like ignoring DHCID or not overwriting entries w/o DHCID.
>
> Ing. Thomas Zenz
> IT-Operations
>
> Oesterreichische Nationalbank
> Garnisongasse 15, 1090 Wien
> T:+43(0)1 40420-2744
> F:+43(0)1 40420 04-2744
> M: +43(0)664 1426188
> [hidden email]
> www.oenb.at
>
>
> Diese E-Mail kann vertrauliche Informationen enthalten und irrtümlich an
> Sie gelangt sein. In diesem Fall informieren Sie bitte sofort die
> Absenderin bzw. den Absender und vernichten Sie diese E-Mail. Das
> unerlaubte Kopieren sowie die unbefugte Weitergabe dieser Mail oder von
> Teilen dieser Mail sind nicht gestattet.
> _______________________________________________
> dhcp-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
>


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Re: What does update-conflict-detection true; do

thomas.zenz@oenb.at
if update-conflict-detection is set to off it ignores all existing records and replaces it with his record!

Server protection is disabled! DHCP-Name-Protection-in-Windows-Server
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