Other protocols monitoring - DNS

In the DNS section you set parameters specific to monitoring DNS-based software services.

General

Two properties are available for controlling the behavior of the DNS analyzer. The DNS query timeout option can be set globally for all software services based on the DNS analyzer, and the DNS query time threshold option can be set either globally or overridden for a user-defined software service based on the DNS analyzer.

You can modify the DNS analyzer behavior by setting the following properties:

DNS query time threshold

The default slow transaction threshold expressed in seconds. If a DNS lookup takes longer than this length of time, but shorter than the timeout value (see below), the transaction is classified as slow. The default value is one (1) second.

The value of the property can also be overridden for a user-defined software service based on the DNS analyzer. When editing a rule for the software service, click the DNS tab to modify the behavior of the DNS analyzer.

DNS query timeout

Server response timeout expressed in seconds. If a DNS lookup takes longer than this length of time, the transaction is classified as failed. The default value is 5 seconds.

Availability

By configuring the availability, you can determine which attempt failures are included in the availability metric calculation.

You can configure DNS availability globally or at the software service level.

For global configuration, open NAM Console ► Deployment ► Manage devices, NAM Probe Configuration ► Open configuration, and go to Global ► Other Protocols Monitoring ► DNS ► Availability. For the software service level, select the Availability tab in the Edit Rule window.

For DNS, you can determine whether the following DNS errors, all enabled by default, should be included in the calculation of Failures (transport) metric.

  • DNS empty response
  • DNS other errors
  • DNS timeouts
  • DNS refused errors
  • DNS name errors