DNS record types · Updated

DNS MX record

An MX (mail exchanger) record names the server that accepts email for a domain, together with a priority. Without an MX record, senders fall back to the domain's A record, which is rarely a mail server.

Look up a MX record

Check what DNS returns right now:

Format and example

example.com.   3600   IN   MX   10   mail.example.com.
  • Name: The domain that receives mail, the part after the @ in an address.
  • Priority: A number. Senders try the lowest first and move to higher numbers only if it is unreachable.
  • Mail server: A hostname with its own A or AAAA record. Never an IP address and never a CNAME.

Common mistakes

  • Pointing the MX at an IP address or at a CNAME. Both are invalid and some senders refuse to deliver.
  • Naming a mail server that has no A or AAAA record. Nothing can connect to it.
  • Mixing old and new providers. Leftover records from a previous provider with the same priority send part of your mail to the wrong place.
  • Forgetting that lower numbers win. A priority of 10 is tried before 20.

Related record types

TXT record, NS record. The DNS record types guide compares them all.

Frequently asked questions

What is an MX record?

An MX record tells other mail servers where to deliver email for your domain. Each record has a priority and the hostname of a mail server.

What does MX priority mean?

Senders try the server with the lowest number first and fall back to higher numbers only if it cannot be reached. Servers with the same priority share the load.

Can an MX record point to an IP address?

No. It must point to a hostname that has its own A or AAAA record. An IP address or a CNAME target is invalid.

What is a null MX?

A single MX record with the target "." (RFC 7505) says the domain does not accept email at all. It lets senders fail immediately instead of retrying.

How do I check my MX records?

Use the lookup above. It shows each mail server, its priority and its IP addresses, and warns about a server that has none.