DNS/DHCP A Record Behavior Change in 21.1.6 (Breaking Change)

[toups]

I recently upgraded to 21.1.6 and suddenly my DNS-dependent scripts started failing. I take advantage of static DHCP entries for a lot of my workstations, servers & pis. To all my DHCP clients, I provide a third-level domain for the dynamic DNS entries. So if my parent domain is example.com, my DHCP clients get internal.example.com as their domain.

Since the upgrade to 21.1.6, all static DHCP clients are provided the parent domain, example.com, for DNS registration instead of the child domain, internal.example.com. However, any dynamic DHCP client gets the expected internal.example.com domain for DNS registration.

I am pretty sure this is related to this entry in the update change log: "unbound: use dhcpd_staticmap() for lease registration"

If you look at the help information for this setting in Unbound DNS, it points to using a domain that is configured in System General Settings: "If this option is set, then DHCP static mappings will be registered in Unbound, so that their name can be resolved. You should also set the domain in System: General setup to the proper value."

That setting on my configuration is the parent domain. The expected behavior from the configuration of the DHCP is that the child domain is registered with the hostname. I have disabled the new setting and my static DHCP clients fail to register a record in DNS.

The short-term fix is to register A records for my static DHCP clients in the child domain. Not terrible but I want to make sure if anyone else was confused like me knows they are not alone.

[sorano]

Have you tried this:

https://github.com/opnsense/core/issues/5027

[toups]

Ran the patch and it appears to have solved the issue. Deleted the A records I created, restarted dhcp & unbound, and record registration looks correct.