DDNS updates for zone having multiple primary servers

glenn.satchell at uniq.com.au glenn.satchell at uniq.com.au
Thu Apr 1 10:53:37 UTC 2021

Hi Kraishak

Options are setting sent to the client to configure the client 
behaviour. ddns-domainame is a setting to configure how dhcpd server 
performs dynamic DNS updates.

option domain-name "example.org";

this is the equivalent of setting the domain function in 
/etc/resolv.conf, that is, it is the domain to add to an unqualified 
name. So if user looks up the name "foo" it will try "foo.example.org". 
See dhcp-options man page for options that are sent to configure the 

ddns-domain-name "desktop.example.org";

this is the domain the dhcp server should add to an unqualified name 
when forming a fully qualified name for updating in the DNS system. So 
host "foo" is to go into DNS as "foo.desktop.example.org". See 
dhcpd.conf man page.

So you might put all your clients in a sub-domain, eg laptop "foo" goes 
in desktop.example.org. But all your servers are in the top level, eg 
server1.example.org. So you would have

option domain-name "example.org";
ddns-domainname "desktop.example.org";


On 2021-04-01 20:16, kraishak wrote:
> Hi Glenn/ Team
> I have one more doubt what is the difference between the options 
> domain-name
> (option-15) and ddns-domain-name, I don't see much difference between 
> them
> can any one please guide me.
> Sorry I know it is too many questions in one thread but I want to get
> clarify before I use these DDNS options
> Thanks in Advance
> Kraishak
> --
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