dhcpd.leases set ddns

[Chris Cox]

On Thu, 2008-04-03 at 10:39 +0200, Andreas Moroder wrote:
> Hello,
> 
> when certain printers ask for a new lease the lease files contains lines 
> of like the following
> 
>    set ddns-fwd-name = "ps-int-sek.sb-brixen.it";
>    set ddns-rev-name = "252.5.53.10.in-addr.arpa.";
>    on expiry or release {
>      switch (ns-update (delete (1, 12, ddns-rev-name, null))) {
>       case 0:
>        unset ddns-rev-name ;
>        break;
>      }
>      switch (ns-update (delete (1, 1, ddns-fwd-name, leased-address))) {
>       case 0:
>        unset ddns-fwd-name ;
>        break;
>      }
>      on expiry or release;
>    }
> 
> 
> For other printer there are no such lines in the lease file.
> 
> Can anyone please tell me what's the reason for this difference ?
> We have a 3.0.4 dhcpd. I know it is old and we plan to switch in the 
> next days.

A guess.. looks like if the printer is off the network 
or (perhaps more importantly) does a dhcp release, in this
scenario, they are saying that they want the DNS entry for
the printer to disappear asap.

Why?  Not sure.

Perhaps there is some piece of automation out there that uses
the presence of the name inside of DNS to indicate the
availability of the printer (like something that is
constantly going to poll the printer by name).