Your network is a mixed environment of Windows, Linux, and UNIX, computers. The routers are
primarily
Cisco and the network uses a T-1 to connect to the Internet. You are experimenting with setting up
a mail server in a production environment for internal use only. You do not want this mail server to
receive any requests from anywhere but the internal network. Therefore you have decided to block
incoming SMTP traffic at the Firewall. Which port will you block at the Firewall?

A.
23

B.
25

C.
53

D.
80

E.
110