NetScaler appliances now support single sign-on (SSO) using the Kerberos 5 protocol. Users log on to a proxy, the Application Delivery Controller (ADC), which then provides access to protected resources.
The NetScaler Kerberos SSO implementation requires the user's password for SSO methods that rely on basic, NTLM, or forms-based authentication. The user's password is not required for Kerberos SSO, although if Kerberos SSO fails and the NetScaler appliance has the user's password, it uses the password to attempt NTLM SSO.
If the user's password is available, the KCD account is configured with a realm, and no delegated user information is present, the NetScaler Kerberos SSO engine impersonates the user to obtain access to authorized resources. Impersonation is also called unconstrained delegation.
The NetScaler Kerberos SSO engine can also be configured to use a delegated account to obtain access to protected resources on the user's behalf. This configuration requires delegated user credentials, a keytab, or a delegated user certificate and matching CA certificate. Configuration that uses a delegated account is called constrained delegation.