Here’s a good command to see which DC the ACS server is querying:
acs troubleshoot adinfo -a
This command is only for advanced troubleshooting and may incur a lot of network traffic
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Local host name: dr-cisco-acs02
Joined to domain: cordero.me
Joined as: dr-cisco-acs02.cordero.me
Pre-win2K name: dr-cisco-acs02
Current DC: grn-dc-dh03.cordero.me
Warning! Unable to locate computer's subnet site in Active Directory.
Please advise your system administrator.
Last password set: 2015-02-04 20:55:00 EST
CentrifyDC mode: connected