Server Continuation

Based on the return code from a previous call to AcceptSecurityContext, the server can wait for a response from the client and can participate in additional exchanges with the client. To continue the authentication protocol, the server repeats calls to AcceptSecurityContext.

The status returned by AcceptSecurityContext is checked to see if the server needs to wait for additional messages from the client. In most authentication protocols, there is the maximum number of exchanges even for mutual authentication. Currently, both the NTLM and Kerberos protocols do mutual authentication with three exchanges.