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300-720 · Question #58

Which of the following types of DNS records deals with mail delivery for a specific domain?

The correct answer is C. MX. The MX (Mail Exchange) DNS record type is the only record explicitly designed to direct email delivery for a domain by pointing to the responsible mail servers.

System Quarantines and Delivery Methods

Question

Which of the following types of DNS records deals with mail delivery for a specific domain?

Options

  • AA
  • BTXT
  • CMX
  • DPTR

How the community answered

(44 responses)
  • A
    7% (3)
  • B
    2% (1)
  • C
    86% (38)
  • D
    5% (2)

Why each option

The MX (Mail Exchange) DNS record type is the only record explicitly designed to direct email delivery for a domain by pointing to the responsible mail servers.

AA

An A record maps a fully qualified domain name to an IPv4 address and has no inherent mail routing function.

BTXT

TXT records store arbitrary text and are used for purposes like SPF policy declarations and DKIM public keys, but they do not instruct other mail servers where to deliver email for the domain.

CMXCorrect

An MX record specifies the hostname of the mail server responsible for accepting email messages on behalf of a domain and includes a priority value to determine server preference, making it the singular DNS record type dedicated to mail delivery routing.

DPTR

A PTR record performs reverse DNS lookups, mapping an IP address back to a hostname, and is used for sending server verification rather than directing inbound mail delivery.

Concept tested: DNS MX record function for email routing

Source: https://datatracker.ietf.org/doc/html/rfc5321

Topics

#DNS records#MX record#Mail delivery#Email fundamentals

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