A database administrator contacts a security administrator to request firewall changes for a
connection to a new internal application. The security administrator notices that the new
application uses a port typically monopolized by a virus. The security administrator denies the
request and suggests a new port or service be used to complete the application’s task. Which of
the following is the security administrator practicing in this example?

A.
Explicit deny

B.
Port security

C.
Access control lists

D.
Implicit deny

Explanation:
Traffic that comes into the router is compared to ACL entries based on the order that the entries
occur in the router. New statements are added to the end of the list. The router continues to look
until it has a match. If no matches are found when the router reaches the end of the list, the traffic
is denied. For this reason, you should have the frequently hit entries at the top of the list. There is
an implied deny for traffic that is not permitted.