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DNS Lookup Tool
Query any DNS record type — A, AAAA, MX, TXT, CNAME, NS, SOA, CAA.
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MX Record Lookup
mx-lookupCheck mail exchanger records and priorities for a domain in seconds.
Enter a target and run the tool.
Results
| Type | TTL | Value |
|---|
About MX Lookup
MX (Mail Exchanger) records tell sending mail servers where to deliver email for a given domain. Each MX record points to a mail server hostname and carries a priority value — lower numbers are tried first, and higher numbers act as fallback servers. A correct MX setup is essential for inbound email reliability: misconfigured records cause bounces, delays, and spam-filter rejections. The AT USE MX lookup tool queries DNS in real time via DNS-over-HTTPS and returns every MX record for the domain you enter, sorted by priority, so you can immediately see which servers handle mail and in what failover order. No account is required, and the results match exactly what a real sending mail server would resolve.
How to look up MX records
- Type the domain you want to inspect into the input field — for example,
example.comorcompany.org. Do not prefix withhttp://orwww. - Click Run lookup. The tool queries a public DNS-over-HTTPS resolver and returns all MX records published for that domain.
- Review each row returned: the priority column (lower = higher priority) and the target hostname column naming the mail server. A domain with two MX records might show
10 mail1.provider.comand20 mail2.provider.com— sending servers trymail1first and fall back tomail2only if the primary is unreachable. - Cross-check the hostnames against the mail provider you expect to be handling inbound email — for example, Google Workspace records include
aspmx.l.google.com, Microsoft 365 includes a*.mail.protection.outlook.comtarget, and Proton Mail usesmail.protonmail.ch.
Results come from a live resolver, so they reflect the current published state of the zone — not your local DNS cache.
What MX records actually control
When a sending mail server (say, Gmail's outbound servers) needs to deliver an email to [email protected], it looks up the MX records for example.com. It then tries to open an SMTP connection to the server with the lowest priority number. If that server is down or refuses the connection, it tries the next-lowest priority. If all MX servers are unreachable, the sending server queues the message and retries for up to four days before returning a bounce.
MX records contain no information about the sender — they only define where inbound mail should land. The SPF, DKIM, and DMARC records (all TXT records) govern whether outbound mail from a domain is accepted by recipients. MX and SPF address different directions of the same email flow.
Priority values are arbitrary integers. The only rule is relative order: the server with the numerically lowest priority gets the first connection attempt. Setting two MX records to the same priority number causes sending servers to pick between them randomly, which is a valid load-distribution strategy. Many Google Workspace setups use five MX entries all sharing different priority numbers; some simple setups use a single MX record with priority 0.
TTL (time-to-live) on MX records controls how long other DNS servers cache the result. Before migrating email providers, lowering the TTL to 300 seconds (5 minutes) a day in advance means old cached values expire quickly once you swap the records — reducing the propagation window from hours to minutes.
Common use cases
- Email provider migration verification — confirm MX records updated correctly after switching from one mail provider to another. Check priority ordering and verify old entries were removed before decommissioning the previous service.
- Bounce and deliverability diagnosis — identify missing, stale, or misconfigured MX records as the first step when inbound email is bouncing or being deferred. Confirm the right mail server hostnames are published and resolvable.
- Domain portfolio audit — audit a group of domains to map which accept email, which use null MX to reject mail, and which have no MX record at all — catching forgotten configurations before they cause problems.
- Vendor domain inspection — inspect a partner or vendor domain to identify their mail provider, verify redundancy, and confirm mail infrastructure matches expected business services.
How to use this tool
- Type the domain whose mail routing you want to inspect (for example, example.com).
- Click "Run lookup" to query the live DNS for MX records.
- Review each MX record returned, noting its priority and target hostname.
- Cross-check the targets against the mail provider you expect to be receiving email.
Frequently asked questions
What does MX priority mean?
Lower numbers mean higher priority. A sending server tries the lowest-priority MX first; higher-numbered entries are fallbacks used only if the primary is unreachable. Setting two MX records to the same number distributes load randomly between them.
How long do MX record changes take to propagate?
Propagation time equals the TTL of the old record — typically 1 to 4 hours for most provider defaults. If you lower the TTL to 300 seconds a day before making the change, new values become visible to all resolvers within minutes of the swap.
Is it normal to have multiple MX records?
Yes. Most production domains publish two or more MX records for redundancy. A primary server handles normal delivery and one or more backup servers catch mail when the primary is temporarily unavailable.
Can a domain have no MX records?
Technically yes — RFC 5321 says senders fall back to the A record if no MX exists. In practice this is almost always a misconfiguration. Domains that intentionally do not accept email should publish a null MX record (priority 0, target ".") to explicitly signal "no mail accepted here," which prevents delivery attempts and avoids queued retry traffic.
Why might this lookup return different results than my DNS provider's dashboard?
Your DNS provider's control panel shows what you have configured, which may not yet have propagated. This lookup queries a live public resolver, so it shows what external senders currently see. Differences usually resolve themselves once the record's TTL expires and the new value propagates.
Do MX records affect email sending, or only receiving?
MX records only control inbound delivery — where other servers send mail addressed to your domain. Outbound sending reputation is governed by SPF (a TXT record), DKIM (another TXT record), and DMARC policy, none of which involve MX records directly.
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