Free tool

MX Record Lookup

Resolve any domain's mail exchange records. See priorities, host IPs, and flags for hostnames that don't resolve.

What the tool checks

It queries the MX records for your domain, parses each one into its priority and hostname, and then resolves each hostname to verify it actually maps to a real server. If you have an MX pointing at a host that no longer exists, this is where you'll see it.

The common breakage

MX records pointing to a hostname that doesn't resolve is the silent failure mode. Senders queue mail and retry for 5 days before giving up, meanwhile your business loses every inbound message during that window. We flag any unresolvable MX hostname as a warning.

What about Null MX?

A domain with 0 . as its only MX record is publishing "we don't receive email, bounce immediately." Useful for marketing-only domains. We detect this and treat it as a valid configuration (not a failure).

FAQ

What does this tool show me?

The MX records published for your domain, sorted by priority, each with the resolved IP addresses. If any MX hostname fails to resolve, we flag it, a common cause of email being held in retry queues.

Why is one MX flagged as "does not resolve"?

The MX record points to a hostname that has no A or AAAA record. This means senders can't actually connect, they'll queue mail and retry for 5 days before bouncing. Usually caused by a typo or a hostname pointing at a decommissioned server.

My MX shows IPs, but I expected hostnames. Why?

You're seeing the resolved A records. The MX record itself points to a hostname; we resolve it to show you the actual server endpoints senders will reach. Click into the result to see both.

Why is priority listed both as 10 and the host?

Priority numbers are arbitrary integers, what matters is relative ordering. Priority 1 vs 5 is no different from 10 vs 50. Senders try the lowest first, then fall through to higher priorities if needed.

MX Records Guide

How email routing works and the most common ways MX setups break.

SPF Checker

MX, SPF, DKIM, and DMARC are stronger together.