Reverse DDNS on classless zones

atif yameen atifyameen at
Wed Jul 18 03:38:16 UTC 2012

I am trying to do reverse DDNS on a classless zone. I have configured my zone declaration in dhcpd.conf as follow:

=======================also in dhcpd.conf====================
subnet netmask
    option subnet-mask;
    option broadcast-address;
    ddns-updates true;
    one-lease-per-client true;
    ping-check false;
    max-lease-time 604800;
    min-lease-time 600;
    default-lease-time 604800;
    do-reverse-updates true;
    dynamic-bootp-lease-length 604800;
    ddns-domainname "";
    ddns-rev-domainname "";

and the following is my reverse zone in named.conf

zone ""
    type master;
    file "4981050.65ED25AA06C49D877204B11DDCB30C43.db";
    allow-transfer { x.x.x.x; };
    allow-update {  <IP-Address-of-DHCP-Server; };
    also-notify { x.x.x.x; };

when a client in the said network obtains an ip address, the dhcp server registers its reverse name as follows :

Jul 17 20:25:37 new dhcpd: Added reverse map from to
where as it should be :

zone file shows the following: (creates a subzone 129 and then a dotted name from the rest of the three octets)

$TTL 302400     ; 3 days 12 hours
250.25.119              PTR

Any Ideas why this is happening?


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