What Is an MX Record?
An MX record — Mail Exchanger record — is a type of DNS record that specifies which mail server is responsible for accepting email on behalf of a domain. When someone sends an email to an address at your domain, their email provider performs an MX lookup to find out where to deliver the message. Without MX records, a domain cannot receive email at all. Every domain that sends and receives business email must have at least one MX record configured in its DNS settings.
Why MX Records Matter for Cold Email Infrastructure
When building a cold email infrastructure on Microsoft Exchange, every sending domain you configure will have MX records automatically created as part of the Exchange setup process. This is because Exchange uses a shared inbox architecture where replies to your cold emails are routed back through your Exchange account. Verifying that your MX records are correctly configured is one of the first checks to run after setting up a new sending domain — before you configure SPF, DKIM, and DMARC, and well before you start warming up your inboxes.
MX Record Priority — What the Numbers Mean
Every MX record includes a priority number. When an email provider attempts to deliver a message to your domain, it contacts the mail server with the lowest priority number first. If that server is unavailable, it tries the next lowest priority number, and so on. Most simple setups have a single MX record with a priority of 0 or 10. More complex setups with redundancy may have multiple records at different priority levels, providing backup delivery paths if the primary server goes down.
How to Use This Tool
Enter any domain — your sending domain, your primary business domain, or a domain you are troubleshooting — and click Check MX Records. Results appear instantly, showing all MX records in priority order and identifying your mail provider automatically. No signup required and completely free.