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Definition
An MX record, short for mail exchange record, is a DNS record that tells other mail servers where to deliver email for a domain. If your domain is example.com.au, its MX record points incoming messages to the email provider that handles mailboxes for that domain, such as Microsoft 365 or another business email platform.
MX records affect incoming email only. They do not usually control where your website loads from, but they sit inside the same DNS zone as website, security and verification records, so changes should be made carefully.
Key Takeaways
- An MX record tells the internet which mail server should receive email for your domain.
- Incorrect MX records can stop incoming email, send mail to the wrong provider, or disrupt an email migration.
- MX records work alongside SPF, DKIM and DMARC, but those records serve different email authentication purposes.
Plain English Explanation
Why MX Records Matter for Business Email
How It Works
How an MX Record Routes an Email
The process happens quickly in the background, but understanding the basic flow helps explain why DNS accuracy matters.
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A sender sends an email to your domain
A customer, supplier or staff member sends a message to an address such as [email protected]. The sending mail server identifies the domain after the @ symbol and needs to find out where that domain receives email.
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The sending server checks DNS for the MX record
The sending server queries DNS for the domain's MX records. The response lists one or more mail servers, often with priority values that tell the sender which server should be tried first.
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The message is delivered to the listed mail server
The sending server connects to the mail server named in the MX record. If that server accepts mail for the domain and the mailbox exists, the message can then move through spam filtering, security checks and mailbox delivery.
MX Record Terms Explained
MX records are easier to understand when the related DNS terms are clear. These are the main terms you may see when reviewing email DNS settings.
- Mail exchanger
- The mail server listed in an MX record. It is the destination that receives email for the domain.
- Priority
- A number that tells sending mail servers which MX record to try first. Lower numbers usually have higher priority.
- TTL
- Time to live. This controls how long DNS resolvers may cache a record before checking for an updated version.
Example MX Record
An MX record is usually displayed as a small DNS table. The exact host name and destination depend on your email provider.
Type: MX
Name: @
Priority: 0
Value: example-com-au.mail.protection.outlook.com
TTL: 3600Illustrative example only. Real Microsoft 365 and third-party email settings should be copied from the provider's current instructions for the specific domain.
MX Records Are Not the Same as SPF, DKIM or DMARC
MX Records Compared with Email Authentication Records
These DNS records often sit together, but they do different jobs. Confusing them can make troubleshooting harder.
| Record Type | Main Purpose | Business Impact |
|---|---|---|
| MX | Routes incoming email to the correct mail server for the domain. | If incorrect, incoming email may fail, go to an old provider, or be delayed. |
| SPF | Lists which servers are authorised to send email for the domain. | If missing or wrong, outgoing email may look less trustworthy to receiving servers. |
| DKIM and DMARC | DKIM signs messages, while DMARC sets a policy for handling failed authentication. | If poorly configured, legitimate messages may be rejected or fraudulent messages may be harder to control. |
Business Impact
What Can Go Wrong When MX Records Are Incorrect?
Common MX Record Problems
These symptoms are common when MX records, DNS propagation or email provider settings are not aligned.
Incoming email has stopped after changing providers
Likely cause
The domain may still have old MX records, incomplete new records, or a mixture of both.
Solution
Check the current DNS zone against the new provider's required settings. During migrations, allow for DNS propagation and test from several external accounts.
Some people can email you, but others receive bounce messages
Likely cause
DNS caching, inconsistent records, or provider-side rejection may be affecting only some senders.
Solution
Review MX records, TTL values, mail server responses and bounce message details. The wording in the bounce message often gives useful clues.
Website forms are not sending notifications
Likely cause
The website may be sending through the wrong mail method, the domain may lack authentication records, or mail may be routed to an unexpected provider.
Solution
Check MX records, SPF, DKIM and DMARC, then test the website form and server-side mail configuration. Forms should be tested after major DNS or hosting changes.
MX Record Mistakes to Avoid
MX changes are small, but they can affect business-critical communication. These mistakes are worth avoiding before a change is made.
Deleting old records before the new email environment is ready
Do this instead
Prepare and test the new mailboxes first where possible. Plan the change so the new provider is ready to accept email when DNS is updated.
Copying settings from another domain without checking provider instructions
Do this instead
Use the exact records generated for the specific domain. Email providers may use domain-specific values, especially for Microsoft 365, DKIM and verification records.
Assuming DNS changes are instant everywhere
Do this instead
Allow for DNS propagation and caching. Lowering TTL before a planned migration may help reduce delay, but it does not remove all third-party caching behaviour.
MX Record Review Checklist
Use this checklist before changing email providers, launching a new domain, or troubleshooting incoming email failures.
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Confirm which provider should receive email
Check whether the domain should route mail to Microsoft 365, Google Workspace, a web host, a legacy provider, or another email platform.
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Review the full DNS zone, not only the MX record
Email reliability can also depend on SPF, DKIM, DMARC, verification records and website form sending methods.
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Plan changes around business impact
For business-critical email, document existing records, take screenshots or exports where possible, and schedule changes when disruption can be monitored.
Professional Support
Can You Manage MX Records Yourself?
Our Approach
How We Approach MX Records, DNS and Business Email
MX Record FAQs
These short answers cover common questions about MX records and business email DNS.
Does an MX record affect my website?
Can I have more than one MX record?
Will fixing my MX record stop emails going to spam?
Need Help Reviewing Your Business Email DNS?
If your emails are failing, landing in spam, or you are planning an email migration, we can review your domain, MX records and authentication settings. We will explain what needs attention and help you plan the next step without unnecessary disruption.