[Kea-users] DDNS remove domain included in fqdn option

[Isaac Brummel]

Hello,

I'm setting up Kea in a Test environment and ran across an issue with DDNS domain names. I have a couple of Windows servers that are domain joined. The domain is different than the domain used by the Kea DDNS service. So when a Windows servers requests a lease an odd record is generated for the client. The windows domain name is "win-domain.com" and the domain used by DDNS is "win-test.com". Here are the hostname specific options received by a tcpdump when the Windows servers requests a lease.

   Hostname (12), length 21: "win11"
   FQDN (81), length 33: "win11.win-domain.com"

This combination results in the DDNS service creating a recording containing "win-domain.com" that I assume is because it's not the Kea DDNS domain and doesn't know how to handle it. The record that gets generated looks like this: "win11.win-domain.com.win-test.com". In the Kea DHCP4 config, I have the following for the DDNS suffix.

   "ddns-qualifying-suffix": "win-test.com",

Looking at the documentation for DDNS there is the "ddns-replace-client-name" option but in my testing it seems that it can't use the value from the incoming packet's option 12 (hostname) and requires statically setting something. Is there a way to work around this issue, removing "win-domain.com" from the DDNS record, or having DDNS ignore the FQDN (81) option all together? Would the "ddns-tuning" hook work for this?

Thanks,
Isaac
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