Check mail exchange records, verify email server configuration, and validate MX priorities
MX (Mail Exchange) records are DNS records that specify the mail servers responsible for receiving email on behalf of a domain. They're essential for email delivery and include priority values that determine the order in which mail servers should be contacted.
MX records tell sending mail servers where to deliver email for your domain. Key components:
Example MX record:
example.com IN MX 10 mail1.example.com
example.com IN MX 20 mail2.example.com
MX priority (also called preference) determines delivery order:
Example scenario: If your primary mail server (priority 10) is down, senders will try the backup server (priority 20) instead.
Proper MX configuration is critical for email delivery:
Single Server (Not Recommended):
example.com IN MX 10 mail.example.com
⚠️ Single point of failure - if server down, no email received
Primary + Backup (Recommended):
example.com IN MX 10 mail1.example.com
example.com IN MX 20 mail2.example.com
✓ Provides redundancy if primary fails
Load Balanced (Same Priority):
example.com IN MX 10 mail1.example.com
example.com IN MX 10 mail2.example.com
✓ Distributes incoming mail randomly across servers
Example of Google Workspace (formerly G Suite) MX configuration:
example.com IN MX 1 aspmx.l.google.com
example.com IN MX 5 alt1.aspmx.l.google.com
example.com IN MX 5 alt2.aspmx.l.google.com
example.com IN MX 10 alt3.aspmx.l.google.com
example.com IN MX 10 alt4.aspmx.l.google.com
Example of Microsoft 365 (Outlook/Exchange) MX configuration:
example.com IN MX 0 example-com.mail.protection.outlook.com
No MX Records Found: Add MX records in your DNS settings. Most domains need at least one MX record to receive email.
Wrong Priority Order: Ensure primary server has lowest priority number. Verify backup servers have higher numbers.
MX Points to CNAME: Change MX to point directly to A record, not CNAME. This violates RFC standards.
DNS Not Propagating: Wait 24-48 hours for changes to propagate worldwide. Check TTL values.
Our tool tests:
Proper MX configuration affects deliverability:
Check all MX records with priorities and mail server details
Get instant MX record information without delays
Get configuration warnings and improvement recommendations
An MX (Mail Exchange) record is a type of DNS record that specifies the mail servers responsible for receiving email for a domain. It includes: (1) The mail server hostname, (2) A priority value that determines order. Without MX records, email cannot be delivered to your domain. The priority value (lower = higher priority) tells sending servers which mail server to try first, with backups available if the primary fails.
Enter your domain name in the checker above and click "Check MX". We'll query DNS servers to retrieve all MX records for your domain and show: (1) All mail servers with priorities, (2) Primary and backup servers, (3) IP addresses for each server, (4) Configuration warnings and recommendations. The results help verify your email configuration is correct.
MX priority (or preference) is a number that determines the order in which mail servers are contacted. Lower numbers have higher priority. Example: Priority 10 is tried before priority 20. If priority 10 is unreachable, the sender tries priority 20. Multiple servers with the same priority share load randomly. Common setup: primary=10, backup=20, tertiary=30. This ensures email delivery even if your primary server is down.
Multiple MX records provide redundancy and reliability: (1) If primary server fails, backup receives mail, (2) No email loss during server maintenance, (3) Better uptime and reliability, (4) Professional email setup. Recommended: At least 2 MX records with different priorities. Example: mail1.example.com priority 10 (primary), mail2.example.com priority 20 (backup). Single MX record means single point of failure - if that server goes down, no email is received until it's back up.
To add or modify MX records: (1) Log into your DNS provider (where domain is registered or hosted), (2) Find DNS management or DNS settings, (3) Add new MX record with hostname and priority, (4) Save changes, (5) Wait 24-48 hours for DNS propagation, (6) Verify with our checker. Most providers have simple forms where you enter: Type=MX, Priority=10, Value=mail.example.com. If using Google Workspace or Microsoft 365, they provide specific MX records to add.
No! MX records MUST point directly to A or AAAA records, never to CNAME records. This is forbidden by RFC 2181. Incorrect: MX → CNAME → A record. Correct: MX → A record. If you need to use a hostname that's a CNAME, create an A record instead or point the MX to the final destination directly. Most DNS validation tools will flag MX pointing to CNAME as an error. Some mail servers may reject or delay email if they encounter this.
Google Workspace: 5 MX records (aspmx.l.google.com with priorities 1, 5, 5, 10, 10). Microsoft 365: Usually 1 MX record (yourdomain-com.mail.protection.outlook.com, priority 0). Custom servers: Typically 2-3 MX records (mail1/mail2/mail3 with priorities 10/20/30). Single server: 1 MX record (not recommended - no redundancy). Always check your email provider's documentation for their specific MX configuration requirements.
MX record changes typically take: (1) Immediate to 15 minutes - on your DNS server, (2) Up to TTL value - for cached records to expire, (3) 24-48 hours - for full global propagation. The TTL (Time To Live) value determines how long DNS servers cache the record. Lower TTL (e.g., 1 hour) means faster updates but more DNS queries. Higher TTL (e.g., 24 hours) means slower updates but less DNS traffic. After making changes, use our checker to verify they've propagated. Different DNS servers worldwide may show old values until TTL expires.