DNS: The scavenging interval <interval value> is not set to a recommended value

Updated: October 15, 2010

Applies To: Windows 7, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012

This topic is intended to address a specific issue identified by a Microsoft Baseline Configuration Analyzer or Best Practices Analyzer scan. You should apply the information in this topic only to computers that have had the DNS Microsoft Baseline Configuration Analyzer or DNS Best Practices Analyzer run against them and are experiencing the issue addressed by this topic. For more information about best practices and scans, see Best Practices Analyzer.

Issue

The server scavenging interval has been set to a non-recommended value of <Interval value>.

Scavenging should be enabled and the scavenging interval should be between 6 hours and 28 days.

Impact

An incorrect value will lead to scavenging being run less or more often than desired.

Setting the scavenging interval to a small value may lead to excessive CPU utilization on the DNS server CPU. The DNS server might also be unable to complete the scavenging process before the start of a new scavenging cycle.

Setting the scavenging interval to a large value will allow DNS records to remain in the DNS database for longer than desired and can cause growth of the DNS database. A large DNS database requires additional server disk space and can delay tasks such as zone transfers. An excessive amount of stale resource records can also degrade DNS server performance and cause DNS clients to experience name resolution problems on the network.

Resolution

Set the server scavenging interval to a value between 6 hours and 28 days.

Membership in Administrators, or equivalent, is the minimum required to complete these procedures. Review details about using the appropriate accounts and group memberships at Local and Domain Default Groups (https://go.microsoft.com/fwlink/?LinkId=83477).

To enable automatic scavenging of stale resource records

1. Click Start, click Run, type dnsmgmt.msc, and then press ENTER. The DNS Manager console will open.

2. In the console tree, right-click the name of the DNS server, and then click Properties.

3. Click the Advanced tab.

4. Select the Enable automatic scavenging of stale records check box.

5. To adjust the Scavenging period, in the drop-down list, select an interval in either hours or days, and then type a number in the text box. A scavenging interval of 7 days is recommended. Configure the interval to be no shorter than 6 hours or longer than 28 days.

Additional considerations

After you enable automatic scavenging of stale resource records on the DNS server, you must also enable scavenging at the zone level. For more information, see Set Aging and Scavenging Properties for a Zone.