Refer to the exhibit, which shows a topology diagram of two separate email domains. Which two statements correctly describe how an email message is delivered from User A to User B? (Choose two.)

Question

Exhibit

Options

• Amx.example1.org will forward the email message to the MX record that has the lowest preference.
• BUser B will retrieve the email message using either POP3 or IMAP.
• CUser A's MUA will perform a DNS MX record lookup to send the email message.
• DThe DNS server will act as an intermediary MTA.

• A
  88% (21)
• C
  4% (1)
• D
  8% (2)

Explanation

Options A and B are correct because MX record preference values operate on a lowest-wins basis - when mx.example1.org (acting as an MTA) relays the message to User B's domain, it queries DNS for MX records and delivers to the server with the lowest preference number (highest priority). Once the message arrives at User B's mail server, User B's email client (MUA) retrieves it using either POP3 (downloads and typically deletes from server) or IMAP (syncs and keeps on server).

Option C is wrong because it's the MTA (outgoing mail server), not the MUA (email client), that performs DNS MX lookups - the MUA simply hands the message off to the MTA via SMTP. Option D is wrong because the DNS server only resolves records; it never handles, stores, or forwards email - that's the MTA's job.

Memory tip: Think of email delivery in three stages - compose (MUA), transport (MTA does DNS MX lookups and SMTP relay), retrieve (MUA uses POP3/IMAP). DNS is always a lookup tool, never a mail carrier.

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