MX Record Lookup
Enter any domain to retrieve its MX records in real time. See every mail server hostname, its priority, and whether email delivery is configured correctly.
What Are MX Records?
MX (Mail Exchange) records are DNS entries that specify which mail servers are responsible for receiving email for a domain. When someone sends an email to user@example.com, the sending server first looks up the MX records for example.com to find where to deliver the message. Without MX records, a domain cannot receive email.
Each MX record has two components: a hostname (the mail server's address) and a priority number. Lower priority numbers have higher preference. When multiple MX records exist, the sending server tries the lowest-priority one first. If that server is unavailable, it falls back to the next lowest priority. This redundancy ensures email delivery even if one mail server goes down.
MX records are the foundation of email delivery. Authentication records like SPF, DKIM, and DMARC protect your outgoing email, but MX records control your incoming email. If your MX records point to the wrong servers or are missing, you will not receive email regardless of how well your other DNS records are configured.
Common MX Record Configurations
Google Workspace
Google Workspace domains typically have five MX records pointing to aspmx.l.google.com and variants with priorities 1, 5, 5, 10, and 10. All are redundant Google mail servers.
Microsoft 365
Microsoft 365 uses a single MX record pointing to a tenant-specific hostname like yourdomainname-com.mail.protection.outlook.com with priority 0.
Self-Hosted or Custom
Self-hosted mail servers typically have one or two MX records. The primary server has the lowest priority number and handles all incoming mail. A backup server with a higher priority catches mail if the primary is unavailable.
Frequently Asked Questions
1. What does it mean if a domain has no MX records?
A domain with no MX records cannot receive email. Sending servers will attempt to fall back to the domain's A record, but most modern mail systems treat missing MX records as undeliverable. If you own the domain and need to receive email, you must add MX records through your DNS provider.
2. Why do some domains have multiple MX records?
Multiple MX records provide redundancy. The sending server tries the record with the lowest priority number first. If that server is down or unresponsive, the sender retries with the next record. This ensures email delivery even during maintenance or outages.
3. What does the priority number in an MX record mean?
The priority number determines which mail server is contacted first. Lower numbers have higher preference — priority 1 is tried before priority 10. When two records have the same priority, servers are chosen at random for load balancing.
4. How long does it take for MX record changes to propagate?
DNS changes typically propagate within 30 minutes to a few hours globally. The TTL (Time to Live) value on your existing records determines how long old values are cached. If the TTL is set to 3600 (1 hour), it may take up to an hour for the change to be visible worldwide.
5. Can I use an IP address in an MX record?
No. MX records must point to a hostname (A or AAAA record), not directly to an IP address. This is an RFC specification. If you try to use an IP address, mail servers will not be able to deliver to your domain correctly.
6. How is MX record lookup related to email deliverability?
MX records control incoming email delivery. If you are troubleshooting delivery issues for your own domain, checking MX records confirms the right mail servers are configured. For email verification, MX record lookups are used to confirm that a domain can receive email — addresses at domains without MX records are typically invalid.
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