Hello to all, I have a domain that has just W2K8 R2 as DCs, Windows XP SP3 as workstations and > 90% servers are Windows 2003. Questions: 1- Can I use AES for Kerberos Authentication (I found text that says that XP support just DES and 3DES, but nothin explicit regarding AES) with XP SP3 as client? If yes, do I need to do something (configuration) so it can be possible? 2- What means this checkbox in user property (i.e. "Use DES encryption types for this account")? That AD will use DES with Kerberos just when the user authenticates? Does the user need to do logon on a workstation that support DES? Best regards, EEOC.