Free MX Checker

Look up MX records for any domain and confirm its mail server is reachable. Perfect for diagnosing bounce issues, validating recipient addresses, and troubleshooting email delivery problems.

Email Tester Inbox Placement Tester 
                    
                        ;; Welcome to Campaign Cleaners MX Lookup Tool
                        1) Please enter the domain name you want to check the MX records for.
                        2) Click the "Check MX Records" Button.
                        3) Wait For results.
Built with ♥ by Henry Timmes · Named contributor to RFC 7489 (DMARC)

What Are MX Records and Why Do They Matter?

MX (Mail Exchange) records are DNS entries that tell the internet which mail server is responsible for receiving email on behalf of a domain. Before any message is delivered, the sending server performs an MX record lookup to find the correct destination. If that lookup fails or returns no records, the message bounces immediately. Understanding MX records is fundamental to diagnosing deliverability problems.

  1. Enter the domain name you want to check (e.g. gmail.com).
  2. Click Check MX Records.
  3. Review the mail server hostnames and their priority values.
  4. If no MX records are returned, the domain cannot receive email and should be suppressed.
  5. Use the results alongside SPF and DMARC checks for a full deliverability diagnosis.
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How MX Records Work

When an email is sent to you@example.com, the sending server queries DNS for example.com's MX records, connects to the returned hostname on port 25, and delivers the message. No MX record means no email delivery.

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Priority and Redundancy

Each MX record has a priority number. Lower numbers are tried first. Most domains publish two or more MX records so that if the primary server is down, a backup takes over automatically, preventing lost messages.

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Common MX Record Issues

Missing MX records cause hard bounces. Misconfigured hostnames that do not resolve cause soft bounces. Parked or expired domains often have no MX records at all, making them safe to suppress from your sending list.

Deliverability Tip: Sending email to a domain with no MX records will always hard bounce. Use this tool to pre-screen recipient domains before importing contact lists or launching campaigns. Removing no-MX domains protects your sender reputation.

MX Record FAQ

An MX (Mail Exchange) record is a DNS entry that specifies which mail server is responsible for receiving email for a domain. Every domain that wants to receive email must have at least one MX record pointing to a valid mail server hostname.

A domain with no MX records cannot receive email. Any message sent to it will result in a hard bounce. This is common with parked domains, expired domains, and domains used only for websites. These addresses should be suppressed from your list.

Yes, and most domains do. Multiple MX records provide redundancy. If the primary mail server (lowest priority number) is unreachable, the sending server tries the next one. Google Workspace, for example, publishes five MX records for failover protection.

MX priority is a numeric value assigned to each mail server record. Lower numbers indicate higher priority and are tried first. For example, a server at priority 1 is preferred over one at priority 10. If two records share the same priority number, traffic is distributed between them equally.

MX records point to a hostname, but that hostname must also resolve to a valid IP address via an A record. If the A record is missing or the mail server is blocking inbound connections on port 25, delivery fails even with correct MX records. SPF, DKIM, and DMARC issues can also cause rejection after connection.

Sending to domains with no MX records is a guaranteed hard bounce. If your list contains many invalid or parked domains, your bounce rate will spike, which damages your sender reputation with mailbox providers. Checking MX records before sending is one of the fastest ways to clean a list and protect deliverability.

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