NetTools is a free AD troubleshooting tool, which provides the ability to troubleshoot, query, report and update Active Directory and other LDAP based directories. It includes over 80 different features to help with AD troubleshooting, including a powerful and feature rich LDAP client with over 280 predefined LDAP queries.
Options include AD Site Browser, overlapping subnets, DC lists, site coverage, IP address allocation
Group management, view member server local group membership, check to infinite loops, group compare
The ability to browser the AD Schema and structure, view schema update history, and AD & Exchange schema versions
A number of options to display HTTP headers, Geo IP, Trace Route, Ping, WhoIs, URL and UNC Checkers
User search, troubleshooting for locked accounts, Org structure, and the history of groups changes for a user