Drag and drop the SMTP components on the left onto their corresponding roles on the right.

DRAG DROP
Drag and drop the SMTP components on the left onto their corresponding roles on the
right.

Answer: See the explanation

Explanation:
MTA – Is the component responsible to move email from sending mail server to the
recipient mail server.
MUA – Is the component that interacts with the end user
POP/IMAP – Is the component responsible to fetch email from the recipient mail server
mailbox to recipient MUA
MDA – Is the component responsible to move the email from MTA to the user mailbox
in the recipient mail server

The following terminology is important in understanding the operation of a mail server.
 Mail User Agent (MUA): The MUA is a component which interacts with end
users directly. Examples of MUA are Thunderbird, MS Outlook, Zimbra Desktop.
Web mail interfaces like Gmail and Yahoo! are also MUA.
 Mail Transfer Agent (MTA): The MTA is responsible for transferring an email
from a sending mail server all the way to a recipient mail server. Examples of
MTA are sendmail and postfix.
 Mail Delivery Agent (MDA): Within a destination mail server, local MTA accepts
an incoming email from remote MTA. The email is then delivered to user’s
mailbox by MDA.
 POP/IMAP: POP and IMAP protocols are used to fetch emails from a recipient
server’s mailbox to recipient MUA.
http://xmodulo.com/how-mail-server-works.html