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See which mail servers handle email delivery for a domain, their priorities, and TTL values — instantly.

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What is an MX record?

An MX (Mail Exchange) record is a type of DNS record that identifies the mail servers responsible for accepting email on behalf of a domain. When someone sends an email to user@example.com, their mail server looks up the MX records for example.com to find out where to deliver the message.

Each MX record contains two key pieces of information: a priority value (also called preference) and the hostname of the mail server. Lower priority numbers indicate higher preference — the sending server tries the lowest-numbered server first.

Properly configured MX records are essential for email delivery. Without them, your domain cannot receive email. Most organizations configure multiple MX records with different priorities to ensure redundancy and high availability.

How to read MX lookup results

When you run an MX lookup, you'll see a table with three columns:

  • Priority — The preference value. Lower numbers are tried first. If two records share a priority, traffic is load-balanced between them.
  • Mail Server — The hostname of the server that accepts mail. This must be a valid hostname with its own A or AAAA record (not a CNAME).
  • TTL — Time To Live in seconds. How long DNS resolvers will cache this record before refreshing.

For example, if you see priority 10 for aspmx.l.google.com and priority 20 for alt1.aspmx.l.google.com, sending servers will try the primary Google server first and fall back to the alternate if it's unavailable.

MX record best practices

Always configure at least two MX records with different priorities for redundancy

Use low TTL values (300-3600s) when planning mail server migrations

Ensure MX hostnames have valid A/AAAA records — never point MX to a CNAME

Test MX records after DNS changes to verify email delivery works

Monitor MX records regularly to detect unauthorized changes that could indicate DNS hijacking

Frequently asked questions

What is an MX record?
An MX (Mail Exchange) record is a DNS record that specifies which mail servers are responsible for receiving email for a domain. Each MX record has a priority value — lower numbers indicate higher priority servers that should be tried first.
Why do domains have multiple MX records?
Multiple MX records provide redundancy. If the primary mail server (lowest priority number) is unavailable, sending servers will try the next server in priority order. This ensures email delivery even during server outages.
What does MX record priority mean?
MX priority is a number that determines the order in which mail servers are contacted. A server with priority 10 is tried before one with priority 20. If two servers have the same priority, the sending server randomly picks one for load balancing.
How do I check if my MX records are configured correctly?
Enter your domain in the tool above. You should see at least one MX record pointing to your email provider's mail servers. If no records appear, your domain cannot receive email. Common providers: Google (aspmx.l.google.com), Microsoft (*.mail.protection.outlook.com).
What happens if a domain has no MX records?
If no MX records exist, sending mail servers will fall back to the domain's A record (RFC 5321). However, this is unreliable and most email will fail to deliver. Every domain that receives email should have proper MX records configured.
What is the TTL on an MX record?
TTL (Time To Live) is how long DNS resolvers cache the MX record before checking for updates. Typical TTL values range from 300 seconds (5 minutes) to 86400 seconds (24 hours). Lower TTLs allow faster propagation of changes but increase DNS query volume.
Can MX records affect email deliverability?
Yes. Misconfigured MX records can prevent email delivery entirely. Additionally, having MX records that point to non-existent servers, using very high TTLs during migrations, or lacking backup MX servers can all impact email reliability.

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