pfSense

Add option to DHCP / DHCPv6 to disable update optimization for DDNS.

If DNS Server is loosing DDNS entries, for example BIND DNS Server on each reconfiguration, it takes days or weeks until the DHCP Server adds entries to DNS Server because the DHCP Server think it has already be done.

disabling update optimization will trigger a DNS update each time the client sends a request for an IP address to DHCP server.

FreeBSD manual:
If the update-optimization parameter is false for a given client,
the server will attempt a DNS update for that client each time the
client renews its lease, rather than only attempting an update
when it appears to be necessary. This will allow the DNS to heal
from database inconsistencies more easily, but the cost is that
the DHCP server must do many more DNS updates. We recommend
leaving this option enabled, which is the default. This option
only affects the behavior of the interim DNS update scheme, and
has no effect on the ad-hoc DNS update scheme. If this parameter
is not specified, or is true, the DHCP server will only update
when the client information changes, the client gets a different
lease, or the client's lease expires