IWA (Integrated Windows Authentication)

An authentication method in which the user name and password, also called credentials, are hashed before they are sent over the network. When Integrated Windows authentication is enabled, the client browser proves its knowledge of the password through a cryptographic exchange with the Web server. If the Active Directory directory service is installed on a domain controller that is running Microsoft Windows 2000 Server or Windows Server 2003, and the client browser supports the Kerberos v5 authentication protocol, Kerberos v5 authentication is used. Otherwise, NTLM authentication is used. Integrated Windows authentication was formerly named NTLM, and is also known as Windows NT Challenge/Response authentication. [Exchange 2007]