NetTools is a free tool, which provides a number of tests and functions to interrogate and troubleshooting issues with Active Directory and LDAP directories.  NetTools uses the same base level API functions as many of the standard Microsoft AD tools and utilities, however, NetTools displays the results and raw error messages returned by these APIs to allows you to see the low level error messages, which helps in identifying underlying issues.

NetTools has nearly 80 different functions which are grouped into the sections listed below to help select the correct function when diagnosing common AD issues. 

          • Access Control
          • AD Replication
          • AD Sites
          • Authentication
          • Groups
          • Group Policies
          • Information
          • LDAP
          • Schema
          • Name Resolution
          • Network
          • Trusts
          • Users
          • Misc

NetTools is a single executable that doesn't require any installation, which makes it ideal for field based troubleshooting. 

NetTools also includes a powerful and feature rich LDAP client that can query, browse, update, and interrogate Active Directory, and other LDAP directories.