Wiindows updates DNS records every 24 hours does dnsupdate regulary update the record to ensure the record is not removed by DNS Scavenging?
Both Windows clients and dnsupdate use the DNS Update Protocol to create/update the DNS records. When creating or update DNS records dynamically Active Directory will enable the "Delete this record when it becomes stale" and records a current timestamp in the records properties.
This means records created or update this way are considered eligible for scavenging.
After installing dnsupdate a hook is added to the DHCP configuration, this hook is dependent on the operating system. Refer to the below for more information
Unlike Windows, dnsupdate only does an update when using the DHCP hook (ie. at DHCP renewal time) or the command is ran interactively (eg. /opt/quest/sbin/dnsupdate 192.168.119.131). If the clients are using DHCP, ensure that the DNS scavenging time (No-refresh + Refresh) is higher than the DHCP renewnal time. If the clients are not using DHCP, then it is advisable to run dnsupdate on a cron job to ensure the record is kept alive. (The cron job needs to be timed frequently enough to ensure the update occurs between ("record timestamp + No-refresh interval" and the "Refresh interval"). Certain operating systems like HPUX only execute the DHCP on bootup.
If DNS scavenging (Enable automatic scavenging of stale records) has not been enabled for the zone (on all DNS servers hosting the domain), and manual scavenging isn't performed this can be ignored.
Refer to Microsoft MSDN article - "Don't be afraid of DNS Scavenging. Just be patient." for more information on DNS scavenging