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MX Lookup

Find the mail servers of a domain, in priority order, with their IP addresses. A quick email snapshot checks the SPF, DMARC and DKIM records as well.

Try:

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What MX records do

MX records tell the world which servers accept email for a domain. Each record has a priority number and a host name. A sending server tries the lowest number first and moves to the next one if it fails. Two records with the same number share the load.

What the lookup shows

  • The MX records sorted by priority, with the TTL.
  • The IP addresses of every mail host, IPv4 and IPv6, so you can see where mail really goes.
  • Problems in the setup, listed under the table (see below).
  • An email snapshot with the SPF record, the DMARC policy and, if you enter a selector, the DKIM key.

Mistakes the checker finds

  • No MX records. A domain without MX records is expected to receive mail on its A record address. That works, but it is rarely what you want, so add MX records.
  • An MX that points to an IP address. The target must be a host name.
  • An MX that points to a CNAME. This is not allowed by the standards, and some mail servers refuse to deliver.
  • An MX host without an address. If the host has no A or AAAA record, mail cannot be delivered to it.
  • A null MX (priority 0 and a dot as the host) means the domain does not accept mail. That is correct for a domain that only sends or sends nothing.

SPF, DKIM and DMARC in one minute

  • SPF is a TXT record that lists which servers may send mail for the domain.
  • DKIM is a public key in a TXT record at selector._domainkey.yourdomain. The sending server signs each message, and receivers check the signature with this key. The selector is chosen by your mail provider, so enter it to look up the key.
  • DMARC is a TXT record at _dmarc.yourdomain that tells receivers what to do when SPF and DKIM fail, and where to send reports.

Typical mail providers

The host names show where mail goes: Google Workspace uses hosts that end in google.com or googlemail.com, and Microsoft 365 uses hosts that end in mail.protection.outlook.com. If you moved your email and the old provider still shows up, check that you removed the old records.

Use the TXT lookup for a closer look at SPF and DMARC, the DNS lookup for all record types, and the DNS record checker to see whether a change has spread. The DNS records guide explains every record type.

Frequently asked questions

How do I check the MX records of a domain?

Enter the domain and press Lookup. The mail servers appear in priority order, with their IP addresses.

What does the MX priority number mean?

Senders try the lowest number first. If that server does not answer, they try the next one. Equal numbers share the load.

What happens if a domain has no MX record?

Mail servers then try to deliver to the address of the domain itself, its A record. It is better to add MX records.

Can an MX record point to an IP address or a CNAME?

No. It must point to a host name that has an A or AAAA record, and not to a CNAME.