MX record lookup for a domain

What MX records are, how to read them (priority number and mail server), why without them you receive no email, how they differ from SPF, DKIM and DMARC and how to spot the most common mistakes. With a free, instant check of any domain.

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Enter your domain and our email-authentication analyser reviews your MX records together with SPF, DKIM and DMARC in seconds: whether they exist, which mail servers they point to and with what priority. The analysis is instant and we don’t store your domain.

What is an MX record?

An MX record (Mail Exchanger, defined in RFC 5321) is the DNS record that tells the internet which servers should receive the email addressed to your domain. When someone writes to [email protected], the sender’s server queries the DNS of yourdomain.com, reads its MX records and thereby knows which machine to connect to in order to deliver the message. Without MX records, the world does not know where to drop your incoming mail. Unlike SPF or DMARC, which are TXT records, MX is its own record type and each domain can have several.

How to read an MX record: priority + host

Each MX record has two parts: a priority number (or preference) and the name of the mail server:

yourdomain.com.   IN  MX   10  aspmx.l.google.com.
yourdomain.com.   IN  MX   20  alt1.aspmx.l.google.com.

The number sets the order of preference and the lower it is, the higher the priority: mail is delivered first to the MX with priority 10 and, only if it does not respond, to the one with 20 (a backup MX). If two records share the same number, mail is spread between them (load balancing). The host must always be a domain name that resolves to an IP address, never the IP itself.

Why they matter: no MX, no incoming mail

MX records are the front door of your email. Without a valid MX you receive no messages: sending servers will not know where to deliver them and the mail will bounce or be lost. A mispointed MX is just as serious: if it points to the wrong server or to a provider you no longer use, your incoming mail ends up in a mailbox you cannot access. The most common case happens during migrations: you change provider (for example, from an old host to Google Workspace or Microsoft 365) but forget to update the MX, and for days your mail keeps going to the old system.

MX versus SPF, DKIM and DMARC: receiving versus authenticating

Confusing them is a frequent mistake. The MX defines the inbound flow: it tells the world which servers to deliver the mail that is sent to you. By contrast, SPF, DKIM and DMARC authenticate the mail you send: they prove that a message claiming to come from your domain is legitimate and not a spoof. They are complementary pieces: the MX handles reception, and the three protocols handle the reputation and protection of your outgoing mail. A healthy mail domain needs both configured correctly.

Common MX mistakes and how to avoid them

The most frequent failures are: pointing the MX to an IP address instead of a hostname (the standard requires a hostname; a raw IP is invalid); using a CNAME alias as the MX target (forbidden by RFC 2181); badly planned priorities, such as unintentionally duplicating the number or giving the backup a higher priority than the primary; forgetting the trailing dot of the name (mail.yourdomain.com.) in some panels, which turns it into a wrong relative domain; and keeping the MX of an old provider after migrating. If your domain deliberately neither sends nor receives email, the correct way to declare it is a Null MX (0 ., RFC 7505), not leaving it empty.

Frequently asked questions about MX records

How do I check my domain’s MX records?

Enter your domain in our free analyser: we query the public DNS and instantly show you whether MX records exist, which mail servers they point to and with what priority, along with SPF, DKIM and DMARC.

What does the priority number in an MX record mean?

It is the delivery preference order. The lower the number, the higher the priority: mail is delivered first to that server and only moves to the next one (higher number) if the first does not respond. Records with the same number share the load between them.

Can I point an MX record to an IP address?

No. An MX target must be a hostname that in turn resolves to an IP address through A or AAAA records, and it cannot be a CNAME alias. Pointing the MX directly to an IP is an invalid configuration that many servers will reject.

Why don’t I receive email if I have MX records?

It is usually because the MX points to the wrong server or to a provider you no longer use (common after a migration), because the priority is misconfigured, or because the destination server is not accepting mail for your domain. Check which host each MX points to and that it is your current provider.

Sources and references

Updated: July 2026 · Informational content; not professional advice.

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