Product and Software: This article applies to all Aruba Mobility Controllers and ArubaOS 3.4.1 and later.
Windows 2003 server implements many different authentication protocols for authenticating users including Kerberos v5 and NT LAN Manager (NTLM). By default, Kerberos is used for authentication.
NTLM was used as the primary authentication mechanism with Windows 4.0 domain controllers. NTLM is still used to authenticate a Windows 2000 or Windows XP professional client in a Windows 4.0 domain. Any Windows NT 4.0 workstation client authenticating to a Windows 2000 or 2003 domain controller also uses NTLM.
If Windows 2003 server and Windows XP client are in use, the Kerberos protocol is used by default. In such cases, NTLM authentication will not work. Windows 2003 server and Windows XP clients can be configured to use NTLM authentication. Refer to Microsoft documentation for details.