MX Record Lookup
Enter a domain to find its MX records and mail server priorities.
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How to use MX Record Lookup
The MX Lookup tool retrieves the mail exchange (MX) records for a domain, revealing which servers are responsible for receiving its email and in what priority order. MX records are the backbone of email delivery: when someone sends a message to you@example.com, their server looks up example.com’s MX records to decide where to deliver it. Use this tool to confirm a newly configured mail provider is correctly published, to diagnose why mail is bouncing, or to see which email service a domain uses before sending to it.
- Enter the domain whose mail configuration you want to inspect.
- Click Lookup to fetch the live MX records from DNS.
- Review each mail server and its priority value.
- Note the lowest-priority host — that is the preferred receiver.
- Cross-check against your mail provider’s recommended records.
How MX priority works
Each MX record has a priority number, and lower numbers are preferred. A sending server tries the lowest-priority host first and falls back to higher numbers only if that host is unreachable, which is how providers build in redundancy. A common configuration lists a primary at priority 10 and a backup at 20. If two records share the same priority, sending servers choose between them at random to spread load. Getting these numbers wrong can route mail to a backup server that is not fully configured, causing delays or bounces.
| Priority | Mail server | Role |
|---|---|---|
| 10 | mail1.example.com | Primary receiver |
| 20 | mail2.example.com | Backup receiver |
MX records and email deliverability
Valid MX records are necessary but not sufficient for reliable email. Receiving servers increasingly check that the domain also publishes SPF, DKIM and DMARC records to prove that mail claiming to be from it is legitimate. If your MX is correct but mail still lands in spam, the next step is to verify those authentication records. Conversely, if mail bounces immediately with a "no route to host" style error, the MX records themselves are usually missing or pointing at a server that no longer accepts mail.
Glossary
- MX record
- A DNS record naming a mail server responsible for receiving a domain’s email.
- Priority
- A number on each MX record; lower values are preferred by sending servers.
- SMTP
- Simple Mail Transfer Protocol — the standard for transferring email between servers.
- Bounce
- A delivery failure notice returned when mail cannot be delivered.
- Fallback
- Using a higher-priority-number backup server when the preferred one is unreachable.
Related reading
Frequently Asked Questions
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Why use MX Record Lookup?
- Real-time DNS lookups using live resolver queries
- Supports IPv4 and IPv6 addresses
- No software to install — runs entirely in the browser
- Results include TTL values and record priority
Common use cases
- Verify DNS propagation after updating nameservers
- Check MX records when troubleshooting email delivery
- Look up SPF/DKIM/DMARC records for email security audits
- Test whether a SSL certificate is valid and up to date
- Find the IP address behind a domain name
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