DDNS not updating after host name change with same MAC address

Željko Puškarić zpuskaric at ztm.hr
Fri Aug 31 08:46:43 UTC 2018

Hi everyone,

I am having a problem with my DHCP server on Debian Stretch (ISC dhcpd 
version 4.3.5, BIND version 9.10.3) with updating DNS when machine which 
had a lease requests a new lease with different host name (when changing 
OS on the machine or booting it from USB). What happens is that old 
hostname (A record and PTR records) gets deleted as it should, but new 
hostname does not get written to DNS.
When new machine registers it gets written to DNS without a problem.
Is there something that I can configure in order to make it write new 
DNS records.
In the log file named does not mention new host name (so I presume dhcpd 
did not send update).

My dhcpd.conf looks like:

default-lease-time 600;
max-lease-time 7200;

ddns-update-style interim;
deny client-updates;
do-forward-updates true;
update-optimization false;
update-conflict-detection true;

subnet netmask {
    option routers;
    option domain-name "test.loc";
    option domain-name-servers,;
    option domain-search "test.loc";
    pool {
        failover peer "failover-partner";

key dhcpupdate {
         algorithm hmac-md5;
         secret my_secret;

zone 1.17.172.in-addr.arpa {
         primary dhcp-01.test.loc;
         key dhcpupdate;

zone test.loc {
         primary dhcp-01.test.loc;
         key dhcpupdate;

Best Regards,

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