Which type of symmetric algorithm operates on plaintext one bit at a time?

A network technician is setting up access for an HVAC technician to do maintenance in the server room. What safeguards need to be in place? (Select all that apply.)

a. Ensure that a guard is on duty. b. Make sure all servers are fully password protected. c. Make sure all monitors are turned off. d. Make sure the water lines are turned off.

Which of the following ports would be blocked if Pete, a security administrator, wants to disable FTP?

A. 21 B. 23 C. 25 D. 110