DNS scavenging and static IP's

Technowiz

I ran into this situation at work and have been trying to track down an answer but no luck yet. DNS scavenging as I understand it will remove DNS records that grow stale beyond the time frame specified in the scavenging settings. If you are using dynamic updates with DHCP then the records don't grow stale as long as the refresh rate isn't too long.

But what about statically assigned IP addresses? Most of our servers have exclusions in the DHCP scope and a static IP address on the NIC. I can run ipconfig /registerdns to create their records in DNS but will they be scavenged later on? Do they have a refresh period that happens automatically or can be configured? Or are they recognized as static and never grow stale? Any clarification would be much appreciated.

faa067

The DHCP Client Service is responsible for registering the server with Dynamic DNS. (that's right the DHCP Client Service, not the DNS client service re.: http://support.microsoft.com/kb/264539) Even for machines with a statically assigned IP address, the DHCP client service will dynamically register with DNS at least once every 24 hours while your server is running.

If you leave the DNS scavenging settings at their defaults (7 days) you should not have any problems with statically assigned IP addresses and dynamic DNS registration.

HTH

Francois

sprkymrk

See if this helps:

http://support.microsoft.com/kb/932464

And also here:
http://support.microsoft.com/kb/816592

Which states in part:

By default, computers that run Windows Server 2003 and that are statically configured for TCP/IP try to dynamically register host address (A) and pointer (PTR) resource records for IP addresses that are configured and used by their installed network connections. By default, all computer register records are based on the full computer name.

[snip]

DNS updates can be sent for any one of the following reasons or events:
• An IP address is added, removed, or modified in the TCP/IP properties configuration for any one of the installed network connections.
• An IP address lease changes or renews any one of the installed network connections with the DHCP server. For example, this update occurs when the computer is started or when you use the ipconfig /renew command.
• You use the ipconfig /registerdns command to manually force an update of the client name registration in DNS.
• The computer is turned on.
• A member server is promoted to a domain controller.
When one of these events triggers a DNS update, the DHCP Client service, not the DNS Client service, sends updates. If a change to the IP address information occurs because of DHCP, corresponding updates in DNS are performed to synchronize name-to-address mappings for the computer. The DHCP Client service performs this function for all network connections on the system. This includes connections that are not configured to use DHCP.

Technowiz

Thanks so much! I spent a good bit of time trying to track down that answer on microsoft and never came across those articles. Even cleared up the other question I had of the dynamic update refresh interval and how to change it. Thanks again!