How do I lookup MX records?

You can use a web tool like this one, or fall back to the command line with 'dig MX example.com' on Linux and macOS or 'nslookup -type=MX example.com' on Windows. Other popular sites such as mxtoolbox.com and dnschecker.org pull from the same authoritative DNS data, so the answers match.

What does priority mean?

Lower numbers win. A server listed at priority 10 is tried before one at priority 20, and several servers sharing the same priority get load-balanced between them. The whole scheme exists so that if a primary mail handler is unreachable, sending servers can fall through to the next one in line.

What if domain has no MX records?

The original RFCs allow sending servers to fall back to the domain's A record, but in practice that's rare on modern mail systems. A domain without MX records typically just doesn't accept email, and messages aimed at it bounce back to the sender.

How can I identify email provider from MX?

The hostnames are usually a giveaway. ASPMX.L.GOOGLE.COM points at Google Workspace, MX.PROTECTION.OUTLOOK.COM at Microsoft 365, MXA.MAILGUN.ORG at Mailgun, and MX.SENDGRID.NET at SendGrid. Many lookup tools automatically label the provider for you, which is handy for vendor audits.

Can MX records be different from A records?

They almost always are. The A record points at the web server's IP, while the MX record points at whoever handles email. A typical setup might run the website on AWS and route mail through Google Workspace — different services, different hosts, same domain.

How long do MX changes take to propagate?

It depends on the TTL of the previous record, which dictates how long resolvers cache the old value. Defaults run from 1 hour up to a day, and a full email migration usually plans 24 to 48 hours for global propagation. Lowering the TTL before the change and raising it afterward keeps the transition window short.

Is the data sent to a server?

MX lookup needs a DNS query, and browsers can't issue raw DNS, so the tool typically routes requests through a DNS-over-HTTPS endpoint at Cloudflare or Google. Your query is visible to that provider, which is fine for ordinary domain lookups but worth knowing if the lookup itself is sensitive.

MX Record Lookup

Look up MX records for any domain online. Free MX lookup tool showing mail server priorities, email providers, and SPF/DMARC records.

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How to Use MX Record Lookup

Enter domain name

Type the bare domain such as example.com without any 'http://' or 'www' prefix. The tool then issues a DNS query for the MX records.

View MX records

Results come back as priority and hostname pairs. The lower priority numbers are tried first by sending mail servers, and multiple entries provide redundancy in case the primary host is unreachable.

Identify provider (auto)

The tool recognizes the hostname patterns of common providers — Google Workspace, Microsoft 365, Mailgun, SendGrid — and labels them automatically. This is handy for vendor audits and quick deliverability troubleshooting.

Verify configuration

Compare what you see against the records your email provider expects. A mismatch usually points at misconfiguration, the wrong provider, or DNS that hasn't finished propagating from a recent change.

When to Use MX Record Lookup

Email deliverability troubleshooting

When emails go missing or bounce, the MX records are usually the first thing to check. They tell you exactly which servers receive mail for a given domain, so a quick lookup often reveals whether the issue is a misconfigured handler, a stale DNS entry, or a third-party email service that has stopped responding.

Email service migration

When you cut over from Gmail to Office 365 (or any other provider), MX changes are what actually flip the switch. Running this lookup against your domain confirms the new records have propagated and that mail is flowing to the right place rather than the previous host.

Spam investigation

A suspicious sender domain often gives itself away through its MX records. Pulling them up shows whether the domain is backed by a legitimate provider like Google or Mailgun, or whether it points at a disposable mail handler that's a hallmark of throwaway phishing infrastructure.

Domain audit

Mapping out which email services your organization actually relies on becomes straightforward with MX lookups across your domains. Auditors use this to build a vendor inventory, spot shadow IT, and decide where consolidation might cut costs.

MX Record Lookup Examples

Standard lookup

Input

Domain: example.com

Output

MX records: 10 mail.example.com, 20 mail2.example.com. Priority numbers (lower = higher priority).

A typical lookup returns one or more priority and hostname pairs. The lower the number, the more preferred that server is. Multiple entries exist so that if the primary mail handler is unreachable, sending servers can fall back to the next one in line.

Common providers

Input

company.com using Google Workspace

Output

MX: 1 ASPMX.L.GOOGLE.COM, 5 ALT1.ASPMX.L.GOOGLE.COM, 5 ALT2.ASPMX.L.GOOGLE.COM, 10 ASPMX2.GOOGLEMAIL.COM, 10 ASPMX3.GOOGLEMAIL.COM

The hostnames Google Workspace uses are unmistakable, and Office 365 (mx.protection.outlook.com), Mailgun (mxa.mailgun.org), and SendGrid (mx.sendgrid.net) follow similar fingerprints. A glance at the records tells you which provider is on the other end.

No MX records

Input

Domain without email

Output

No MX records found. Domain doesn't accept email or uses A record fallback (legacy).

Plenty of domains aren't set up to receive mail at all and simply have no MX entries. Mail aimed at them bounces. A handful of older configurations rely on the A-record fallback the RFC permits, but that's rare on modern setups.

Tips & Best Practices for MX Record Lookup

1.Subdomains can carry their own MX records, so mail.example.com might route somewhere completely different from example.com itself. Always query the exact host you care about rather than assuming the parent domain's records apply.
2.Priority numbers are exactly what they sound like. Lower wins, ties get load-balanced, and the redundancy list exists so a temporarily unreachable primary doesn't take your mail down with it.
3.You can usually identify the provider at a glance once you know the patterns. Google's aspmx.l.google.com, Microsoft's mx.protection.outlook.com, Mailgun's mxa.mailgun.org, and SendGrid's mx.sendgrid.net all show up regularly.
4.MX is the explicit, modern way to route mail; the A-record fallback is a quirk of older specs that very few servers still honor. If you see only an A record, expect deliverability problems.
5.DNS changes don't take effect instantly. The TTL on the previous record dictates how long the old value sticks around in caches, often 24 to 48 hours, so plan email migrations with that window in mind.
6.MX is only one piece of the email-authentication puzzle. SPF lists who's allowed to send for you, DKIM signs outbound messages, and DMARC ties the two together. A full audit pulls all four.

Frequently Asked Questions

MX (Mail Exchange) records are DNS entries that tell sending mail servers which hosts handle incoming email for a domain. Each record has a priority number and a hostname, so a record like '10 mail.example.com' means 'try this server with priority 10'. Multiple records exist so a primary mail server can fail over to a backup without losing mail.

MX Record Lookup

What are MX Records?

How MX Priority Works

Common Email Providers and Their MX Records

Related Email & DNS Tools

How to Use MX Record Lookup

Enter domain name

View MX records

Identify provider (auto)

Verify configuration

When to Use MX Record Lookup

Email deliverability troubleshooting

Email service migration

Spam investigation

Domain audit

MX Record Lookup Examples

Standard lookup

Common providers

No MX records

Tips & Best Practices for MX Record Lookup

Frequently Asked Questions

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