Key Port Numbers

Question 1

Port 20

Answer 1

File Transfer Protocol (FTP)

For sending and receiving files

Question 2

Port 21

Answer 2

File Transfer Protocol (FTP)

Control

Question 3

Port 22

Answer 3

Secure Shell (SSH) 
For secure logins to computers

Question 4

Port 25

Answer 4

Simple Mail Transfer Protocol (SMTP) for sending email

Question 5

Port 80

Answer 5

HyperText Transfer Protocol (HTTP)

For browsing web pages.