A virtual private network (VPN) is the extension of a private network that encompasses links across shared or public networks like the Internet. A VPN enables you to send data between two computers across a shared or public internetwork in a manner that emulates the properties of a point-to-point private link. The act of configuring and creating a virtual private network is known as virtual private networking. To emulate a point-to-point link, data is encapsulated, or wrapped, with a header that provides routing information allowing it to traverse the shared or public transit internetwork to reach its endpoint. To emulate | MS-CHAP v2 is an updated encrypted authentication mechanism that provides stronger security for the exchange of user name and password credentials and determination of encryption keys. With MS-CHAP v2, the NAS sends a challenge to the access client that consists of a session identifier and an arbitrary challenge string. The remote access client sends a response that contains the user name, an arbitrary peer challenge string, and an encrypted form of the received challenge string, the peer challenge string, the session identifier, and the user's password. The NAS checks the response from the client and sends back a response containing an indication of the success or failure of the connection attempt and an authenticated response based on the sent challenge string, the peer challenge string, the encrypted response of the client, and the user's password. The remote access client verifies the authentication response and, if correct, uses the connection. If the authentication response is not correct, the remote access client terminates the connection.
