Directory Utility

Directory Utility is a utility included with the macOS (previously Mac OS X) operating system to configure connections to directory services.
In OS X 10.6 to 10.9, Directory Utility is in the /System/Library/CoreServices/ - it can be accessed through the GUI via the Accounts System Preferences panel, after clicking 'Join' next to Network Account Server, and then clicking 'Open Directory Utility. '
In OS X 10.10 Directory Utility moved to /System/Library/CoreServices/Applications.
Prior to Mac OS X 10.5, this tool was named Directory Access.