Mac Client connecting to Windows 2012 Domain

All,

Our company bought two new iMac machine with OSX 10.8.2 and need to connecting to Windows 2012 Domain. We can Join the Mac client to AD member but cannot authenticate to AD. Only local user can log on to Machine.

I want to ask that any service require or configuration on windows server 2012. Any thing need to configure on Mac OSX ?

thanks

Keith