Windows Server 2008 R2 includes numerous support tools for configuring, managing, and troubleshooting Active Directory. Here is a brief overview of some of the most useful support tools and their executable.

ADSI Edit (Adsiedit.msc)
Opens and edits the Active Directory Services Interface for domain, schema, and configuration containers.

Active Directory Administration Tool (Ldp.exe)
Performs Lightweight Directory Access Protocol (LDAP) operations on Active Directory.

Directory Services Access Control Lists Utility (Dsacls.exe)
Manages access control lists (ACLs) for objects in Active Directory.

Distributed File System Utility (Dfsutil.exe)
Manages the Distributed File System (DFS) and displays DFS information.

DNS Server Troubleshooting Tool (Dnscmd.exe)
Manages properties of Domain Name System (DNS) servers, zones, and resource records.

Replication Diagnostics Tool (Repadmin.exe)
Manages and monitors replication using the command line.

Windows Domain Manager (Netdom.exe)
Allows domain and trust relationships management from the command line.

From the Microsoft Press book Windows Server 2008 Administrator’s Pocket Consultant, Second Edition by William R. Stanek.