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