What Is an MX Record
Learn what an MX record is, how incoming email routing works, MX priority, and how MX differs from website DNS records.
Introduction
MX stands for Mail Exchanger. When someone sends email to you@example.com, sending servers look up MX records to find where to deliver the message.
MX records point to hostnames (like mail.example.com or aspmx.l.google.com), not directly to mailbox names. Those hostnames still need valid DNS resolution.
Quick answer
An MX record tells the internet which mail servers should receive email for your domain. Lower priority numbers are tried first. MX controls incoming mail delivery — not website hosting and not which servers are allowed to send mail.
What it means
An MX record pairs a priority number with a mail server hostname. Sending servers try lower priority values first, then fall back to higher numbers if needed.
- Controls where incoming email is delivered
- Uses priority — lower number = higher priority
- Multiple MX records can provide redundancy
- Does not control website hosting (that is A/CNAME)
- Does not authorize outbound sending (that is SPF/DKIM/DMARC)
Where you see this:
- Google Workspace, Microsoft 365 and other hosted email
- cPanel, Plesk and hosting-panel mail
- Backup MX services for failover
- Email provider migrations
example.com. 3600 IN MX 10 mail.example.com.
example.com. 3600 IN MX 20 backup.example.com.Why this matters
Wrong or missing MX records mean email never reaches your inbox — even when the website works fine. MX is often changed accidentally during website migrations.
How to check it
- Run MX Lookup on your domain.
- Confirm MX hostnames match your email provider.
- Check priority values and whether backup MX is intentional.
- Verify each MX hostname resolves with DNS Lookup.
- Send a test message after any MX change.
Look up MX records
Use MX Lookup to see which mail servers receive email for a domain.
Common mistakes
MX deleted during website migration
HighWebsite DNS was updated but mail records were removed.
Next step: Restore MX records for your email provider before closing old hosting.
MX still points to old provider
HighMail continues routing to a previous host after email migration.
Next step: Update MX to the new provider and wait for DNS propagation.
Wrong priority order
MediumBackup MX is tried before primary or an old server has lower priority.
Next step: Set the active provider to the lowest priority number.
MX hostname missing A record
HighThe mail server name in MX does not resolve.
Next step: Add A/AAAA for the MX hostname or use the provider’s correct hostname.
Changing MX when only the website moved
MediumMail routing was changed unnecessarily during a web hosting move.
Next step: Update A records for the site; leave MX unless email also moved.
Example
example.com. 3600 IN MX 1 aspmx.l.google.com.
example.com. 3600 IN MX 5 alt1.aspmx.l.google.com.Frequently asked questions
Does MX control outgoing email?
No. Outbound sending uses SMTP servers and authentication records like SPF, DKIM and DMARC. MX is for incoming delivery.
Can I have multiple MX records?
Yes. Multiple MX records with different priorities provide redundancy and failover.
What does MX priority mean?
Lower numbers are higher priority. Mail servers try the lowest priority MX first.
Do MX records affect my website?
No. Website traffic uses A, AAAA or CNAME records. MX only affects email delivery.
Related tools
Use these free tools to verify your configuration after applying changes.
Related guides
Browse all Glossary guides →Need help applying this fix?
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