MS-CHAP is used for which type of authentication?

• A. initial
• B. message-by-message
• C. Both A and B
• D. Neither A nor B

Answer: (A)

MS-CHAP is a challenge-response method used during the initial establishment of a PPP connection. In this process, the server issues a random challenge to the client, and the client replies with a value derived from the password’s hash. The server verifies this response, authenticating the user before any data is transferred. It isn’t used for ongoing, per-message authentication of every packet; that would imply continuous authentication of each message, which isn’t how MS-CHAP is designed. So, its role is to validate identity at the start of the connection.