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    MX Record Checker

    Look up the MX records for any domain. Validate priority ordering, redundancy and target reachability.

    Check MX records

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    What is an MX record?

    An MX (Mail Exchanger) record is a DNS record that tells sending mail servers which hosts are responsible for receiving email for your domain. Each record carries a numeric priority and a target hostname; senders try lower priorities first and fall back through the list for redundancy.

    A typical MX configuration looks like this:

    example.com.   IN MX   1   smtp.google.com. example.com.   IN MX   5   alt1.smtp.google.com. example.com.   IN MX   10  alt2.smtp.google.com.

    What this MX checker validates

    CheckWhat it means
    PresenceAt least one MX record is published at the domain root.
    Priority orderingRecords have valid 16-bit priorities and a defined preference order.
    Public reachabilityEvery MX target resolves to a public A or AAAA address.
    No CNAME at targetMX targets are not CNAMEs (forbidden by RFC 2181 §10.3).
    No IP literalMX targets are hostnames, not raw IP addresses.
    RedundancyMore than one host is published to survive a single-server outage.
    Null MX detectionA single MX of '.' with priority 0 (RFC 7505) means the domain accepts no mail.

    Common MX targets by provider

    ProviderMX hosts
    Google Workspacesmtp.google.com (priority 1)
    Microsoft 365<tenant>.mail.protection.outlook.com
    Proton Mailmail.protonmail.ch, mailsec.protonmail.ch
    Fastmailin1-smtp.messagingengine.com, in2-smtp.messagingengine.com
    Zoho Mailmx.zoho.com, mx2.zoho.com, mx3.zoho.com
    iCloud Mail (custom domain)mx01.mail.icloud.com, mx02.mail.icloud.com

    How to fix common MX problems

    • If no MX records are returned, publish at least one valid MX entry at your domain root
    • Replace CNAME-at-MX with the canonical A/AAAA-resolvable hostname (RFC 2181 §10.3)
    • Replace IP literals in MX targets with proper hostnames
    • Publish at least two MX hosts on different infrastructure for redundancy
    • Use priorities that reflect your intended order — equal priorities load-balance
    • If the domain should never receive mail, publish a Null MX (0 .) per RFC 7505 rather than leaving it empty

    Frequently asked questions

    Related free tools

    References

    Go beyond one-off checks

    Safer Sender continuously monitors your domain's DMARC, SPF and DKIM, classifies every sender, and guides you safely from p=none to p=reject.

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