eG Monitoring
 

Measures reported by DNSSerCheckTest

A virtual switch can be attached to one and only one physical NIC. Each Virtual / Legacy NIC plugs into a virtual switch.

If the DNS server is inaccessible or is unable to provide domain name resolution services, then users may be denied access to their mission-critical servers and applications. Under such circumstances, you may want to quickly check what is stalling the operations of your DNS server, so that the source of the issue can be isolated and eliminated. This test enables you to perform such a check, periodically. To perform this check, this test uses the DCDIAG utility that ships with Windows 2003 Support Tools and is built into Windows 2008 R2 and Windows 2008 Server. DCDIAG is a command-line tool that encapsulates detailed knowledge of how to identify abnormal behavior in a system. For validating DNS health, the DCDIAG utility runs six tests, each of which reports the current state of a critical performance aspect of the DNS server; these DNS tests are as follows:

  • Authentication: This test is run by default and checks the following:
    • Are domain controllers registered in DNS?
    • Can they be pinged?
    • Do they have Lightweight Directory Access Protocol/Remote Procedure Call (LDAP/RPC)?
  • Basic: Performs basic DNS tests, including network connectivity, DNS client configuration, service availability, and zone existence.
  • Forwarders: Performs the Basic tests, and also checks the configuration of forwarders
  • Delegation: Performs the Basic tests, and also checks for proper delegations
  • Dynamic Update: Performs the Basic tests, and also determines if dynamic update is enabled in the Active Directory zone
  • Record Registration: Performs the Basic tests, and also checks if the address (A), canonical name (CNAME) and well-known service (SRV) resource records are registered. In addition, creates an inventory report based on the test results.
The DNSSerCheckTest test uses the DCDIAG.exe to execute each of the above-mentioned tests at configured intervals, reports the output of each test, promptly captures current/potential DNS failures, and provides detailed diagnostics describing the reasons for the failure. This way, administrators are enabled to troubleshoot DNS-related issues quickly and efficiently.

Note:

For this test to run, the DCDIAG.exe should be available in the <WINDOWS_INSTALL_DIR>\windows\system32 directory of the DNS server to be monitored. The DCDIAG utility ships with the Windows Server 2003 Support Tools and is built into Windows 2008 R2 and Windows Server 2008. This utility may hence not be available in older versions of the Windows operating sytem. When monitoring the AD server on such Windows hosts, this test will run only if the DCDIAG.exe is copied from the <WINDOWS_INSTALL_DIR>\windows\system32 directory of any Windows 2003 (or higher) host in the environment to the same directory on the target host.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Ser_status Reports the output returned by this test.   Each test that DCDIAG runs will report one of the following values as the output:

  • Fail
  • Pass
  • Warning

This test will report the same output as the value of the Ser_status measure.

The numeric values that correspond to these outputs are indicated below:

Output/Measure name Numeric value
Fail 0
Pass 1
Warning 2

Note:

By default, this measure reports the Output/Measure Values listed in the table above as values of the Status measure. In the graph of the Status measure however, these measure values are represented using their numeric equivalents only - i.e., 0 to 2.

You can use the detailed diagnosis of this measure to view detailed descriptions of failures (if any). This information will help in investigating the reasons for the failure and fixing them.