Windows Active Directory

Client Commands

List Applied GPO's

GUI:

 rsop.msc

CLI:

 gpresult /r /scope computer

or save it to an html file with /h:

 gpresult /h c:\gpresult.html

Confirm DC is Reachable

 net view \\<DC name>

Domain Controller Admin

Show DC Replication Status

This also shows the DSA object GUID of all DC's.

 repadmin /showrepl

Show replication state and relative health of a forest

 repadmin /replsummary

Sync Domain Controller with all Replication Partners

 repadmin /syncall /d /e

Domain Controller Diagnostics

Verify DNS Services for DC

 dcdiag /test:dns

Comprehensive, Run all tests, Verbose

 dcdiag /c /v

Force registration of all DC-specific DNS records

 nltest.exe /dsregdns

Check DC FSMO Roles

 netdom query FSMO

Enable LDAPS

Essentially, all you have to do is generate a SSL Server Certificate with the CN={hostname_of_dc} and place it into the Computer Certificates > Personal cert store. The DC will automatically use the server cert in there with the most longevity. You don't even need to restart any services nor the server itself (in my experience, anyway).

Using Linux BIND DNS Servers for Dynamic AD Updates

See ISC BIND.