FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -Microsoft Challenge Handshake Authentication Protocol version 2 (MS-CHAP v2) is a password-based authentication protocol which is widely used as an authentication method in PPTP-based (Point to Point Tunneling Protocol) VPNs.

Detailed explanation-2: -Under UNIX or Linux environment, SSH is used for VPN. PPTP uses the same authentication protocols as PPP (a communication protocol for making connection between two parties through dial-up), such as EAP, CHAP, PAP, and SPAP to authenticate the identity of the remote user.

Detailed explanation-3: -CHAP (Challenge-Handshake Authentication Protocol) is a challenge and response authentication method that Point-to-Point Protocol (PPP) servers use to verify the identity of a remote user.

Detailed explanation-4: -CHAP uses a three-way handshake to be able to authenticate. Once the client and the server initially connect, the server will send a challenge message to the client. The client combines the password with that challenge message and sends a hash back to the server.

Detailed explanation-5: -EAP-Extensible Authentication Protocol The latest version is standardized in RFC 5247. The advantage of EAP is that it is only a general authentication framework for client-server authentication-the specific way of authentication is defined in its many versions called EAP-methods.