What is the MD5 algorithm used for？（）

A.The ACL applied to the vty lines has no in or out option like ACL being applied to an interface.
B.The ACL is applied to the Telnet port with the ip access-group command.
C.The ACL must be applied to each vty line individually.
D.The ACL should be applied to all vty lines in the in direction to prevent an unwanted user from connecting to an unsecured port.

A.It cannot support UDP flows.
B.It cannot ensure each TCP connection follows a legitimate TCP three-way handshake.
C.It cannot detect application-layer attacks.
D.The status of TCP sessions is retained in the state table after the sessions terminate.

A.A router interface can belong to multiple zones.
B.Policy maps are used to classify traffic into different traffic classes， and class maps are used to assignaction to the traffic classes.
C.The pass action works in only one direction
D.A zone-pair is bidirectional because it specifies traffic flowing among the interfaces within the zone-pair in both directions.