A security analyst noticed a colleague typing the following command:
`Telnet some-host 443’
Which of the following was the colleague performing?

A.
A hacking attempt to the some-host web server with the purpose of achieving a distributed
denial of service attack.

B.
A quick test to see if there is a service running on some-host TCP/443, which is being routed
correctly and not blocked by a firewall.

C.
Trying to establish an insecure remote management session. The colleague should be using
SSH or terminal services instead.

D.
A mistaken port being entered because telnet servers typically do not listen on port 443.

Explanation:
B: The Telnet program parameters are: telnet <hostname> <port>
<hostname> is the name or IP address of the remote server to connect to.
<port> is the port number of the service to use for the connection.
TCP port 443 provides the HTTPS (used for secure web connections) service; it is the default SSL
port. By running the Telnet some-host 443 command, the security analyst is checking that routing
is done properly and not blocked by a firewall.