MX Record Lookup

Check mail exchange (MX) records and DNS configuration for any domain. Verify email server setup instantly.

What are MX Records?

Mail Exchange (MX) Records: DNS records that specify the mail servers responsible for accepting email messages on behalf of a domain

Priority Levels: Lower numbers indicate higher priority. Mail is sent to the server with the lowest priority number first

Email Deliverability: Proper MX records are essential for receiving emails at your domain

Redundancy: Multiple MX records provide backup mail servers if the primary server is unavailable

Understanding MX Records and Email Routing

Mail Exchange (MX) records are DNS entries that define which mail servers are responsible for receiving email on behalf of a domain. When someone sends you an email, the sending server performs an MX lookup to discover which server to deliver the message to. Without valid MX records, a domain cannot receive any email — making MX lookup a fundamental step in email infrastructure diagnosis.

Each MX record contains two components: the mail server hostname and a priority number. Lower priority numbers indicate preferred servers — if the primary server is unavailable, the sending server automatically tries the next one in priority order. This built-in redundancy is why professional email setups typically have multiple MX records from different servers.

Common mail providers have distinctive MX record patterns: Google Workspace uses aspmx.l.google.com, Microsoft 365 uses *.mail.protection.outlook.com, and independent servers typically show the domain itself or a mail subdomain. Recognizing these patterns quickly identifies which email infrastructure a domain uses.

Diagnosing Email Delivery Problems with MX Lookup

MX lookup is the starting point for diagnosing email delivery failures. When emails to a domain consistently fail to deliver, checking MX records immediately reveals whether the issue is DNS configuration or mail server availability. A domain with no MX records has no email capability — any address on that domain is guaranteed to bounce. Misconfigured MX records pointing to non-existent servers produce similar delivery failures.

For email marketers and administrators, MX lookup provides insight into the email infrastructure used by recipient domains before sending. Knowing that a domain uses Google Workspace, Microsoft 365, or a specific regional provider helps predict how email will be handled — including filtering policies, authentication requirements, and typical delivery speeds.

When setting up email for a new domain, MX lookup verification confirms that DNS changes have propagated correctly. DNS propagation can take up to 48 hours, and MX lookup allows you to check progress in real-time rather than waiting for delivery failures to confirm whether records are active.

MX Records and Email Authentication

MX records work in conjunction with other DNS-based email authentication standards — SPF, DKIM, and DMARC — to establish domain email legitimacy. While MX records define where to deliver email, SPF records specify which servers are authorized to send email from your domain. Together, these records create a complete email security framework that protects against spoofing and phishing.

For system administrators setting up email, verifying MX records is just the beginning of a complete DNS audit. SPF records should list all authorized sending servers, DKIM public keys should be published in TXT records, and DMARC policies should specify how receivers handle authentication failures. MX lookup is therefore typically used alongside SPF, DKIM, and DMARC checking tools as part of a comprehensive email infrastructure audit.

Understanding which mail provider handles a domain's MX records also informs authentication setup — each provider has specific requirements for SPF includes and DKIM selector configurations. Our tool displays the full MX record set with priorities, giving you everything needed for accurate infrastructure assessment.

Frequently Asked Questions