Configuration of DnsTest

Active Directory uses DNS as its domain controller location mechanism and leverages the namespace design of DNS in the design of Active Directory domain names. As a result, DNS is positioned within the discoverability and logical structure components of Active Directory technology components. If a user complaints of being unable to access an AD domain, then administrators should first check whether the DNS component of AD is available and is able to resolve the IP address of the domain to its corresponding domain name and vice-versa. This is where, the DnsTest test will be useful!

This test emulates a client accessing DNS to issue a query. The query can either request DNS to resolve a domain name to an IP address or vice versa. Based on the response reported by the server, measurements are made of the availability and responsiveness of the DNS component of the AD server.

The default parameters associated with this test are as follows:

• The TEST PERIOD list box helps the user to decide how often this test needs to be executed.

• In the HOST text box, the host name of the server for which the test is to be configured has to be specified.

• Specify the port on which the specified host is listening in the PORT textbox.

• The IP address or host name to be resolved during the test in the TARGETS text box. Multiple TARGETS can be specified as a comma-separated list.

• The DNS supports two types of queries. For a non-recursive query, DNS attempts to respond to the request based on its local cache only. For a recursive query, a DNS server may use other DNS servers to respond to a request. The Recursive flag can be used to determine the type of queries to be issued to DNS.

• Specify the port at which the DNS server listens in the DNS PORT text box.

• If multiple components of the same component type are awaiting configuration, then an APPLY TO OTHER COMPONENTS check box will appear in this page. Clicking on this check box will allow you to apply the configuration to all/selected components of that type.

• Once the necessary values have been provided, clicking on the Update button will register the changes made.

When changing the configuration for specific servers, a “*” beside the text box corresponding to the parameter signifies that these values have to be manually configured by the user. The parameter values that require to be configured will typically be prefixed with a “$” or contain a series of “*”. A value of "none" in the parameter value indicates that the corresponding parameter value can be changed if required.