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+17 votes

Which of the following transport layer protocols is used to support electronic mail?

  1. SMTP
  2. IP
  3. TCP
  4. UDP
asked in Computer Networks by Veteran (355k points)
edited by | 2.6k views

4 Answers

+29 votes
Best answer

Answer is option C: TCP.

There are three primary TCP/IP protocols for E-Mail management:

  • Post Office Protocol (POP)
  • Simple Mail Transfer Protocol (SMTP)
  • Internet Message Access Protocol (IMAP)

They all are Application Layer Protocols

Once a client connects to the E-mail Server, there may be 0(zero) or more SMTP transactions. If the client has no mail to send, then there are no SMTP transactions. Every e-mail message sent is an SMTP transfer. 

SMTP is only used to send (push) messages to the server. POP and IMAP are used to receive messages as well as manage the mailbox contents(which includes tasks such as deleting, moving messages etc.).

answered by Boss (30.7k points)
edited by
question asks for transport layer protocol..

So does that mean none of  using UDP as transport layer protocol ?

  • Post Office Protocol (POP)
  • Simple Mail Transfer Protocol (SMTP)
  • Internet Message Access Protocol (IMAP)

client and server state source kuros 

+10 votes
ans c)

SMTP is used in Application Layer.
answered by Active (5.2k points)
+9 votes

TCP is used in transport layer to carry out mail which is iniated by application layer protocol SMTP.

So correct option will be -TCP

answered by Loyal (8.8k points)
+6 votes
E-mail uses SMTP, application layer protocol which intern uses TCP transport layer protocol.
answered by Active (2.1k points)

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