Which of the following authentication methods prevents unauthorized execution of code on remote syst

Which of the following authentication methods prevents unauthorized execution of code on remote
systems?

A.
TACACS

B.
S-RPC

C.
RADIUS

D.
CHAP

Explanation:
Secure RPC (Remote Procedure Call) is an authentication method used to authenticate
the user and the host. It also prevents unauthorized
execution of code on remote systems. S-RPC uses the Diffie-Hellman and DES mechanisms. It is
required for the applications to have the NFS
and the NIS+ name service if they use Secure RPC.
Answer option C is incorrect. Remote Authentication Dial In User Service (RADIUS) is a networking
protocol that provides centralized access,
authorization and accounting management for people or computers to connect and use a network
service. When a person or device connects

to a network often authentication is required. RADIUS is commonly used by ISPs and corporations
managing access to the Internet or internal
networks employing a variety of networking technologies, including modems, DSL, wireless and
VPNs.
Answer option A is incorrect. 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 D 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.