Some of the command line utilities below go back to 2003 Server, but still work in a 2008 R2 environment. The first command is nltest. To list the existing domain controllers for a domain, use the command:
nltest /dclist:domain name
The following switch will return a list of domain controllers and the corresponding IP addresses.
The netdom command can return a list of which server has what role within Active Directory.
netdom query fsmo
The command below should return replication information when executed on a domain controller.
The dcdiag command will return several parameters when executed on a domain controller. Individual tests can also be performed. For example, the command below just tests for DNS issues.
If you change the IP address of a domain controller, this command will update the DNS Service Principal Name (SPN) records.