250+ TOP MCQs on SMTP and Answers

Computer Networks Multiple Choice Questions on “SMTP”.

1. Simple mail transfer protocol (SMTP) utilizes _________ as the transport layer protocol for electronic mail transfer.
a) TCP
b) UDP
c) DCCP
d) SCTP

Answer: a
Clarification: Since TCP is a reliable protocol, it’s more efficient to use TCP protocol for e-mail transfer. TCP also provides more security than other transport layer protocols.

2. SMTP connections secured by SSL are known as _____________
a) SMTPS
b) SSMTP
c) SNMP
d) STARTTLS

Answer: a
Clarification: SSMTP is a simple mail transfer program to send mail from a local PC to a mail host. SNMP is a network management protocol. STARTTLS connections are secured by TLS.

3. SMTP uses which of the following TCP port?
a) 22
b) 23
c) 21
d) 25

Answer: d
Clarification: Port 21 is used for FTP control connection, port 22 is used by SSH, and port 23 is used by TELNET.

4. Which one of the following protocol is used to receive mail messages?
a) SMTP
b) Post Office Protocol (POP)
c) Internet Message Access Protocol (IMAP)
d) FTP

Answer: d
Clarification: FTP is used to share files. SMTP, POP and IMAP are the protocols used to send and receive mails on the internet.

5. What is on-demand mail relay (ODMR)?
a) protocol for SMTP security
b) an SMTP extension
c) protocol for web pages
d) protocol for faster mail transfer

Answer: b
Clarification: ODMR is an extension to SMTP, in which mails are relayed to the receivers after they are authenticated. It allows only the authorized receivers to receive the mail.

6. An email client needs to know the _________ of its initial SMTP server.
a) IP address
b) MAC address
c) URL
d) Name

Answer: a
Clarification: The client needs to know the IP of its initial SMTP server as it has to send the mail first to that server and then the server forwards the mail ahead on behalf of the user.

7. An SMTP session may not include _______
a) zero SMTP transaction
b) one SMTP transaction
c) more than one SMTP transaction
d) one HTTP transaction

Answer: d
Clarification: An SMTP session can only include SMTP transactions regardless the number. Any other protocol’s transaction is not included in an SMTP session.

8. SMTP defines _______
a) message transport
b) message encryption
c) message content
d) message password

Answer: a
Clarification: As the name suggests, Simple Mail Transfer Protocol is only responsible for “how” the message is transferred i.e. Transport of the message. Other protocols such as TCP are used to provide other services like encryption for the messages.

9. Which one of the following is an SMTP server configured in such a way that anyone on the internet can send e-mail through it?
a) open mail relay
b) wide mail reception
c) open mail reception
d) short mail reception

Answer: a
Clarification: Anyone can send an e-mail through an Open Mail Relay server so it acted like a free relay for email agents to forward their mails through. Open Mail Relays are now unpopular because they can be used by attackers to perform man-in-the-middle attacks.

10. SMTP is not used to deliver messages to ______
a) user’s terminal
b) user’s mailbox
c) user’s word processor
d) user’s email client

Answer: c
Clarification: SMTP can only be used to send messages to user’s terminal, email client or mailbox. A stand-alone word processor cannot be connected to a network, so it won’t be possible to deliver messages to it.