A network consists of various remote sites that connect back to two main locations. Pete, the security
administrator, needs to block TELNET access into the network. Which of the following, by default, would be the
BEST choice to accomplish this goal?

A.
Block port 23 on the L2 switch at each remote site

B.
Block port 23 on the network firewall

C.
Block port 25 on the L2 switch at each remote site

D.
Block port 25 on the network firewall

Explanation:
Telnet is a terminal-emulation network application that supports remote connectivity for executing commands
and running applications but doesn’t support transfer of files. Telnet uses TCP port 23. Because it’s a clear text
protocol and service, it should be avoided and replaced with SSH.