AD: Active Directory Tools

Onboard


Event Logs

DCDIAG
Domaincontroller Diagnostic Tools

NETDIAG
Showing issue for the DC network

DNSLINT
For checking DNS

NETSH
DHCP, Network options

Repadmin
Replication tool


Data Collector Sets
Performance Diagnostics for AD, System and more.




FREE Third Party Tools


AD Topology Diagrammer(Visio required)

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=13380

AD Tidy Free Edition
Query AD for last logged on Attributes of User/Computer accounts. Move Delete  and more options available.
http://www.cjwdev.co.uk/Software/ADTidy/Info.html

AD Info Free Edition
Query AD for Information about AD objects
http://www.cjwdev.co.uk/Software/ADReportingTool/Info.html

LIZA
Analyse ACL on Active Directory
http://www.ldapexplorer.com/en/liza.htm

LUMAX
LDAP Explorer and Maintenance
http://www.ldapexplorer.com/en/lumax.htm