DDNS updates for secondary DNS server

glenn.satchell at uniq.com.au glenn.satchell at uniq.com.au
Tue Apr 27 08:06:11 UTC 2021


Hi Kraishak

My understanding is that each time the DHCP server renews a lease it 
will try to update the DNS server if the record does not exist. So this 
could take some time to catch up if the DNS server is down. I don't 
think it tries to ever update the secondary - this is the job of the 
primary. For this reason a lot of sites implement the dhcp server on the 
same box as the dns server.

Also looks like something in your DNS config may not be quite right. In 
dhcp your primary is 192.168.0.45, but it is trying to update 
192.168.0.86 and gets an error. Can you check through both the dhcp and 
dns configuration to see if you mention 192.168.0.86 anywhere?

regards,
Glenn

On 2021-04-27 17:33, Kraishak Mahtha wrote:
> Hi All,
> 
>  zone example.com [1].
>         {
>             primary 192.168.0.45;
>           secondary 192.168.0.47;
>         }
> I have noticed that DHCP is not sending any DDNS updates to the
> secondary DNS server(192.168.0.47) of the zone when the primary is
> down for some reason, is this the expected behavior?
> 
> Getting below error
>  Unable to add forward map from n54c5-000001.example.com [2] to
> 192.168.0.86 [3]: NOTIMP
> 
> Does any one have any idea/experience of DDNS flow when primary DNS
> server is down
> 
> Thanks in Advance
> Kraishak
> 
> 
> Links:
> ------
> [1] http://example.com
> [2] http://n54c5-000001.example.com
> [3] http://192.168.0.86
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