[Kea] Unable to disable pushing Search Domains via DHCP

[nox-404]

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Describe the bug

I tried to disable search domain using the method provided here https://github.com/opnsense/core/issues/6918, but it doesn't accept a . in the search domain field on Kea.

To Reproduce

Steps to reproduce the behavior:

1. Go to Services > Kea DHCP > Kea DHCPv4 > Subnets
2. Click on any subnet
3. Add a . in the search domain list field
4. Save
5. See error Please specify a valid list of domains

Expected behavior

Be able to save. The underlying feature I'm looking for is to be able to prevent OpnSense from pushing any DNS search domains via DHCP

Additional context

Very similar issue as https://github.com/opnsense/core/issues/6918

Environment

Software version used and hardware type if relevant, e.g.:

OPNsense 25.1.6_4-amd64

[demarey-baker]

Recently switched and having this same issue. I used to do this with the additional options on ISC like this: https://blog.duklabs.com/setting-a-blank-dhcp-searchdomain-on-opnsense/ . It is annoying since windows is always appending the extra dns suffix.

[OPNsense-bot]

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