The Netlogon service on a Windows 2000 domain controller will log one or more of these System events if it does NOT receive a 'success' message from the DNS server that owns the zone of the record that is being registered/deregistered.

The event log may contain:

   Netlogon 5774 - Registration of the DNS record <record_name_and_dns_info> failed.                                 Netlogon 5775 - Deregistration of the DNS record <record_name_and_dns_info> failed.                                 Netlogon 5781 - Dynamic registration or deregistration of one or more DNS records failed.
The Netlogon service performs DDNS registrations and deregistrations when the service starts, at regular intervals theeafter, and when the service stops.

NOTE: See tip 2408 ยป How do I Enable/Disable Windows 2000 Dynamic DNS registrations?.

Possible reasons for NOT receiving a 'success' message are:

                              Domain controller configuration: DNS server entries in the TCP/IP properties of the                                                               domain controller are not properly configured.                              Connectivity:                    This domain controller does not have IP, or TCP/UDP                                                               connectivity to the DNS servers that own the zones                                                               to which records need to be registered or deregistered.                              DNS server configuration:        The DNS server cannot accept dynamic updates or is                                                               not configured to accept dynamic updates. If the DNS                                                               server that is used by the DC is not authoritative                                                               for the zones to which the Netlogon service is                                                                attempting to register or deregister, the DNS server                                                               must be able to provide this DC the IP address of the                                                               DNS servers that are authoritative for the affected zones.