Computer networks MCQ - Why SMTP is a 'PUSH' protocol?

Multiple choice questions in Computer Networks, What for SMTP is used? Why do we refer to SMTP as 'PUSH' protocol? What are the 'POP' mail protocols?

 

MCQ on Simple Mail Transfer Protocol

1. Which among the following protocols is an example of “push” protocol?

(a) Simple Mail Transfer Protocol (SMTP)

(b) Post Office Protocol (POP)

(c) Internet Mail Access Protocol (IMAP)

(d) Domain Name Service (DNS)

Answer: (a) Simple Mail Transfer Protocol (SMTP) Why SMTP is referred as a ‘PUSH’ mail protocol? SMTP is a push protocol; it pushes the message from the client to the server. There are two other aspects of mail delivery, though: delivering the mail to the central mail server, and sending outgoing mail. For sending an email, SMTP is used twice; to push the mail from sender to the sender's mail server, and to send the mail from source server to the destination mail server(s). As it happens, both these tasks are handled by push mail protocols, so called because the sender initiates push mail transfers. Majority of the mails delivered on the Internet uses SMTP. SMTP uses sender-push model where the sender knows the identity of a receiver in advance and pushes the message in an asynchronous manner to the receiver. The receiver accepts the entire message, may choose to optionally examine the message, and then accept or discard it. You cannot pull emails off the server using SMTP. POP and IMAP are examples of pull mail protocols.

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What for SMTP is used? 

Why do we refer to SMTP as 'PUSH' protocol? 

What are the 'POP' mail protocols?

SMTP uses sender-push traffic delivery model