MX Records Explained: How Email Routing Works & How to Check MX Records

What Are MX Records?

MX (Mail Exchange) records are DNS records that specify which mail servers are responsible for receiving email on behalf of your domain. When someone sends an email to user@example.com, the sending server queries your domain’s MX records to find where to deliver the message.

Without correct MX records, your domain will not receive any email – messages will bounce or be lost. That’s why setting up MX correctly is essential for any business or personal domain.

How MX Records Work – Priority & Load Balancing

Every MX record has two components:

• Priority (or preference) – a number indicating the order of use. Lower numbers have higher priority.
• Mail server hostname – the server that accepts email for your domain.

Example MX record:

example.com.  MX  10  mail.example.com.
example.com.  MX  20  backup.mail.example.com.

Here, the primary server (priority 10) is used first. If it’s unavailable, the secondary server (priority 20) will handle delivery. This provides redundancy.

Common MX Configurations (Email Providers)

Google Workspace (formerly G Suite)

MX 1  ASPMX.L.GOOGLE.COM.
MX 5  ALT1.ASPMX.L.GOOGLE.COM.
MX 5  ALT2.ASPMX.L.GOOGLE.COM.
MX 10 ALT3.ASPMX.L.GOOGLE.COM.
MX 10 ALT4.ASPMX.L.GOOGLE.COM.

Microsoft 365 (Office 365)

MX 0  yourdomain.mail.protection.outlook.com.

Custom/Third‑Party Hosting

Your hosting provider will give you a mail server address, usually like mail.yourdomain.com or a shared server (e.g., mail.example-hosting.net).

How to Check MX Records for Any Domain

You can verify MX records instantly using our free DNS Checker Tool. Simply enter the domain name, select “MX” record type, and run the lookup.

👉 Check MX Records for Any Domain

The tool will display:

• All MX records (priority + mail server).
• TTL (Time to Live).
• Whether the records are properly published.

This helps you troubleshoot email delivery issues or verify that your changes have propagated.

Common MX Record Problems & Fixes

No MX Records Found

If your domain has no MX record, mail servers will attempt delivery using the domain’s A record (fallback). Many modern mail providers will reject email if no MX exists. Fix: Add at least one MX record pointing to your email provider.

Wrong Priority Values

If your primary mail server has a higher priority number (e.g., 20) than your backup (e.g., 10), email will go to the backup first. Fix: Ensure the server you want as primary has the lowest number.

Pointing to an Invalid Hostname

The mail server hostname must resolve to an IP address. Use our DNS Checker to verify the A record of the mail server exists. If it doesn’t, email will fail.

TTL Too High After Migration

If you switch email providers, old MX records with a high TTL will cause some senders to deliver to the old server for hours or days. Fix: Lower TTL to 300 seconds (5 minutes) at least 24 hours before the migration.

External Resources for Email Deliverability

For advanced email authentication (SPF, DKIM, DMARC) and troubleshooting, these external sites provide excellent tools and guides:

• woorldtv.com – offers email header analyzers and spam score checkers.
• cartpostal.net – printable MX record configuration templates and email migration checklists.

Frequently Asked Questions (FAQ)

Can I have multiple MX records with the same priority?

Yes. This enables load balancing – email will be distributed among servers with equal priority. Use this for high‑volume mail systems.

What is the difference between an MX record and an A record?

An A record maps a domain to an IP (for web traffic). MX records specifically direct email. They are separate; you need both for a functional domain.

How long do MX changes take to propagate?

Usually a few minutes to 48 hours, depending on the TTL set on your old MX records. Always lower TTL well before a migration.

Why do my MX records show my domain name but no IP?

MX records store hostnames (like mail.example.com), not IP addresses directly. The mail server’s A record provides the IP. Always check that the mail server’s A record is correct.

What happens if I delete all MX records?

Your domain will stop receiving email. Senders will get a permanent error (no mail exchanger). Only delete MX if you no longer want email at that domain.

Verify Your MX Records Now

Whether you’re setting up email for a new domain or troubleshooting delivery issues, start by checking your MX records. Use our DNS Checker to see exactly what the world sees. Compare that to your email provider’s documentation – and you’ll usually find the fix in minutes.