Which of the following is a protocol that permits a remote access server to communicate with an authentication server for determining whether the user has access to the network?
A.
EAP
B.
PEAP
C.
CHAP
D.
TACACS
Explanation:
Terminal Access Controller Access-Control System (TACACS) is a remote authentication protocol that is used to communicate with an authentication server commonly used in UNIX networks. TACACS allows a remote access server to communicate with an authentication server in order to determine if the user has access to the network. TACACS allows a client to accept a username and password and send a query to a TACACS authentication server, sometimes called a TACACS daemon. It uses UDP port 49 as the default port.
Answer option C is incorrect. Challenge Handshake Authentication Protocol (CHAP) is an authentication protocol that uses a secure form of encrypted authentication. Using CHAP, network dial-up connections are able to securely connect to almost all PPP servers. Answer option A is incorrect. Extensible Authentication Protocol (EAP) is an authentication protocol that provides support for a wide range of authentication methods, such as smart cards, certificates, one-time passwords, public keys, etc. It is an extension to Point-to-Point Protocol (PPP), which allows the application of arbitrary authentication mechanisms for the validation of a PPP connection. Answer option B is incorrect. Protected Extensible Authentication Protocol, Protected EAP, is a method to securely transmit authentication information, including passwords, over wired or wireless networks. PEAP uses server-side public key certificates to authenticate the server. It then creates an encrypted SSL/TLS tunnel between the client and the authentication server. In most configurations, the keys for this encryption are transported using the server’s public key. The ensuing exchange of authentication information inside the tunnel to authenticate the client is then encrypted and user credentials are safe from eavesdropping.