Microsoft 365 Certified: Administrator ExpertDeploy and manage a Microsoft 365 tenantMedium
A Microsoft 365 administrator is configuring email routing for a new custom domain, 'example.com', which will be used for all user mailboxes in Exchange Online. After adding and verifying the domain, the administrator needs to ensure that all incoming emails for 'example.com' are correctly delivered to the Exchange Online mailboxes. Which type of DNS record must be configured for email to flow correctly to Exchange Online?
- AA record
- BMX record
- CCNAME record
- DSRV record
Show answer & explanationAnswer & explanation
Correct answer: B. MX record
The MX (Mail Exchanger) record is a critical DNS record type that specifies the mail servers responsible for accepting email messages on behalf of a domain name. For Exchange Online, the MX record must point to the Microsoft 365 mail servers to ensure proper email delivery.
Why the other options are wrong
- A. A records map hostnames to IP addresses, primarily for website access, not email routing.
- C. CNAME records create aliases for domain names, used for services like autodiscover, but not the primary mail routing.
- D. SRV records identify hostnames and port numbers for specific services, like SIP, but not for general email delivery.
DNS MX Record for Email Routing
A DNS record that specifies the mail servers responsible for receiving email messages on behalf of a domain name, essential for directing email to the correct mailboxes in Exchange Online.
- Mandatory for incoming email delivery.
- Must point to the Microsoft 365 mail servers (e.g., example-com.mail.protection.outlook.com).
- Can have a priority value to specify preferred mail servers.
Memory trick: The MX record is like the post office sign, pointing all emails to the correct mail delivery service.