when is a DHCP server supposed to remove A and PTR records?

[Marc Haber]

Hi,

I am using DHCP server 4.3.2, running on Debian stable. The server is
configured to create DNS records for clients:

default-lease-time 14400; # 12 hours
max-lease-time 14400;  # 12 hours
not authoritative;
ddns-rev-domainname "in-addr.arpa.";

zone ka51.zugschlus.de. {
  primary lasso.ka51.zugschlus.de;
  key lasso-chasse-dhcp;
}

subnet 192.168.182.0 netmask 255.255.255.0 {
  pool {
    range 192.168.182.150 192.168.182.249;
    failover peer "chasse-cadencia"; # the other side does not exist yet
  }
  option routers int182.barrida.ka51.zugschlus.de;
  ddns-domainname "ka51.zugschlus.de";
  authoritative;
}

zone 182.168.192.in-addr.arpa. {
  primary lasso.ka51.zugschlus.de;
  key lasso-chasse-dhcp;
}

The server creates A and PTR records just fine:

[1/499]mh at lasso:~$ dig +noall +answer @::1 grml.ka51.zugschlus.de. -t ANY; dig +noall +answer @::1 150.182.168.192.in-addr.arpa. -t ANY
grml.ka51.zugschlus.de. 150     IN      A       192.168.182.150
grml.ka51.zugschlus.de. 150     IN      DHCID   AAABXpcYBFwbrFx8RVNPtzwhrrTkbLs/asQOPK8nr65lFtc=
150.182.168.192.in-addr.arpa. 150 IN    PTR     grml.ka51.zugschlus.de.

Under which circumstances is the server supposed to remove the DNS
records? From the docks, I reckon that it should remove them when the
lease expires. According to the logs of the DNS server, it doesn't,
though.

Is that the expected behavior? I'd like systems that are not up to not
be in DNS either. Can this be configured, and if yes, how?

Any hints will be appreciated.

Greetings
Marc

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