Which protocol authenticates connected devices before allowing them to access the LAN?
Correct Answer: D
Explanation/Reference:
Explanation:
802.1X authentication involves three parties: a supplicant, an authenticator, and an authentication server.
The supplicant is a client device (such as a laptop) that wishes to attach to the LAN/WLAN. The term
'supplicant' is also used interchangeably to refer to the software running on the client that provides
credentials to the authenticator. The authenticator is a network device, such as an Ethernet switch or
wireless access point; and the authentication server is typically a host running software supporting the
RADIUS and EAP protocols.
The authenticator acts like a security guard to a protected network. The supplicant (i.e., client device) is not
allowed access through the authenticator to the protected side of the network until the supplicant's identity
has been validated and authorized. An analogy to this is providing a valid visa at the airport's arrival
immigration before being allowed to enter the country. With 802.1X port-based authentication, the
supplicant provides credentials, such as user name/password or digital certificate, to the authenticator, and
the authenticator forwards the credentials to the authentication server for verification. If the authentication
server determines the credentials are valid, the supplicant (client device) is allowed to access resources
located on the protected side of the network.