dynamic dns, bind + dhcpd problem

[Dr. Michael J. Chudobiak]

Hi,

I have dhcpd set up to register dhcp clients to bind, supposedly with a 
TTL of 43200 (12 hours). However, the registration is actually lost 
after 3600 seconds (1 hour). Why?

Here's the log of registration and deletion:

Jan  7 09:12:54 server2 dhcpd: DHCPREQUEST for 192.168.0.97 from 
08:00:86:1a:a1:cc (MLT1AA1CC) via eth0
Jan  7 09:12:54 server2 dhcpd: DHCPACK on 192.168.0.97 to 
08:00:86:1a:a1:cc (MLT1AA1CC) via eth0
Jan  7 10:12:54 server2 dhcpd: if MLT1AA1CC.domain.avtechpulse.com IN 
TXT "31aacbf084144284a227ccfaec56201572" rrset exists and 
MLT1AA1CC.domain.avtechpulse.com IN A 192.168.0.97 rrset exists delete 
MLT1AA1CC.domain.avtechpulse.com IN A 192.168.0.97: success.


The key parts of my dhcpd.conf are:


ddns-update-style interim;
ddns-updates on;
ddns-ttl 43200;
ddns-rev-domainname "in-addr.arpa";
ddns-domainname "domain.avtechpulse.com";

authoritative;

default-lease-time 43200;
max-lease-time 43200;

option ....<snipped>......

ignore client-updates;

subnet 192.168.0.0 netmask 255.255.255.0 {
         range dynamic-bootp 192.168.0.20 192.168.0.99;
         allow unknown-clients;
         }

... <the rest is snipped> ...



Why is dhcpd removing entries after 3600 seconds? Any suggestions?


- Mike