Which of the following protocols allows an e-mail client to access e-mails that are stored on a
remote mail server?

A.
PPPoE

B.
IMAP

C.
SMTP

D.
ICMP

Explanation:

IMAP stands for Internet Message Access Protocol. This protocol helps to retrieve e-mail messages
stored on a shared e-mail server. Through this protocol, a user can use a client e-mail program/Mail
User Agent (MUA) for downloading an e-mail from the shared server. A user can also use this
protocol to edit or delete an e-mail from the shared e-mail server. An example of the IMAP protocol
is the POP3 protocol that is quite simple and used for retrieving e-mails from a mail server.
Answer option C is incorrect. Simple Mail Transfer Protocol (SMTP) is a protocol for sending e-mail
messages between servers. E-mailing systems use this protocol to send mails over the Internet.
SMTP works on the application layer of the TCP/IP or OSI reference model. The SMTP client typically
initiates a Transmission Control Protocol (TCP) connection to the SMTP server on the well-known
port designated for SMTP, port number 25. However, e-mail clients require POP or IMAP to retrieve
mails from e-mail servers. Answer option A is incorrect. Point to Point Protocol over Ethernet
(PPPoE) is a specification for establishing PPP connections through Ethernet network adapters. It
connects users on an Ethernet to the Internet through a common broadband medium, such as a
single DSL line or cable modem. PPPoE is described in RFC 2516. Answer option D is incorrect.
Internet Control Message Protocol (ICMP) is a maintenance protocol and is normally considered part
of the IP layer. ICMP messages are encapsulated within IP datagrams, so that they can be routed
throughout an internetwork.
Reference: “http://en.wikipedia.org/wiki/Internet_Message_Access_Protocol”