dirt is a new utility in Leopard that can be used to test Directory Services. You can use dirt to test authentication for LDAP or Active Directory. The -u flag uses the username from the node you are testing against, in the above example it is the Active Directory username. dirt tests whether an account exists in any node and can be used with the following structure:
dirt -u username -n
This would result in the following output if the account is located in Active Directory:
User username was found in: /Active Directory/domainname
The -p flag can also be used to test passwords. You can also specify the node in Directory Services you would like to test against rather than rely on dirt to cycle through all available nodes.