DDNS updates for zone having multiple primary servers

Simon Hobson dhcp1 at thehobsons.co.uk
Fri Apr 2 09:12:46 UTC 2021

kraishak <kraishak.edu at gmail.com> wrote:

> Thanks for your explanation about the "option domain-name" and
> "ddns-domainname", So based on my network-level setup we configure this
> values, these values can be same or can be different


> And want to confirm one more point that the zone section will be added only
> for the "ddns-domainname" value am i right ?

I don't quite understand the question here, however ...

The process the server will take is roughly :

Client gets a lease, the server will take it's hostname (whether provided by the client, or provided by the config (e.g. in a host declaration)) and join it with ddns-domainname to form a FQDN for the client.

IFF an existing lease record indicates that DNS updates have already been done for this client&FQDN (and the server hasn't been told to always do updates), then that's it. Otherwise ...

It will then lookup the primary server for the client's domain. If there is a matching zone statement, then it will use the primary server specification given there, if not then it will do a DNS lookup for the SOA record of the zone and use the primary server specified in that.

The server will then attempt to do the DNS updates, which may fail if there are clashes or stale data in the zone.


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