update static leases

Glenn Satchell Glenn.Satchell at uniq.com.au
Wed Aug 22 13:59:25 UTC 2007

>Date: Tue, 21 Aug 2007 21:51:31 +0200
>From: Richard Smits <R.Smits at tudelft.nl>
>To: dhcp-users at isc.org
>Subject: update static leases
>Can anyone please give me some information about this ? I am confused.
>The following scenario :
>ISC DHCP server with the folowing (relevant) options :
>ddns-hostname=                 host-decl-name;
>ddns-update-style              interim;
>ddns-updates                   on;
>zone domain.net.              {primary; key DHCP_UPDATER;}
>use-host-decl-names on;
>update-static-leases on;
>subnet netmask {
>  option domain-name             "domain.net";
>Folowing are the host statements......
>DDNS updates are working fine, but the records of old pc's are NOT
>removed. If I read the manual right, the "update-static-leases on" flag
>is the reason for this, because :
>It is not recommended because the DHCP server has no way
>to tell that the update has been done, and therefore will not delete the
>record when it is not in use.
>Now the big question : If I CHANGE an IP number or a Hostname , will the
>record be updated ???
>The record excists, so the server would be able to change it, right ?
>Greetings, and thanks for the info .

As the IP address is assigned with a fixed-address statement, you can
do this the other way round. Manually set up the DNS entries, then in
dhcpd.conf use the *hostnames* in the fixed-address statement. When you
want a new IP address for that host, change the entry in DNS, restart
dhcpd, and the next time the client renews it will get the new address
that matches the hostname.


More information about the dhcp-users mailing list