How to Check MX Records for a Domain
MX records tell you which servers receive a domain's mail. Here is how to look them up, how to read priority, and what a missing MX record means for deliverability.
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Before any mail reaches [email protected], the sending server has to ask one question: which machine actually receives email for acme.com? The answer lives in the domain's MX records. If you are verifying addresses or chasing a deliverability problem, knowing how to read MX is the first move.
What an MX record is
MX stands for mail exchange. It is a DNS record that points a domain at the hostnames of its mail servers, each with a priority number. A typical lookup for a Google Workspace domain looks like this:
acme.com. MX 1 aspmx.l.google.com.
acme.com. MX 5 alt1.aspmx.l.google.com.
acme.com. MX 10 alt2.aspmx.l.google.com.Lower priority numbers are tried first. The 1 server is the primary; the others are backups for when it is busy or down. The hostnames also tell you who runs the mail: google.com here means Google, outlook.com would mean Microsoft, and a domain pointing at itself often means a self-hosted server.
What it tells you about an address
MX is a domain-level signal, not a mailbox one. It cannot tell you whether jordan exists, but it tells you something just as useful at the top of the funnel:
- MX records present. The domain can receive mail. Worth probing the individual mailbox.
- No MX, but an A record. Many servers will fall back to the domain's A record (its plain IP). Mail can sometimes still land, but it is a weaker setup.
- No MX and no A record. The domain cannot receive mail at all. Every address there is undeliverable. You can cull the whole batch from that domain without probing a single mailbox.
A parked domain, a typo domain (
gmial.com), or a dead company domain will usually show no MX. That single lookup saves you from probing addresses that were never going to work.
How to look them up
On the command line, dig acme.com MX +short or nslookup -type=mx acme.com returns the records. That works, but you have to read priorities yourself and it tells you nothing about whether the result is healthy.
The free MX lookup does the same query and shows you the records in priority order with the provider identified, so you can see at a glance whether a domain is set up to receive mail. It does not save the domain you check.
MX is one signal in a larger picture. To see SPF, DKIM, DMARC, and blacklist status together, run a deliverability scan, or read more on MX record validation.
Start with 500 free validation credits. No credit card.
Both Free and Pro run the same scan engine — full SMTP probe, MX lookup, typo, disposable, domain checks, and the evidence chain on every verdict. The difference is the monthly credit pool (Free=500, Pro=100,000) plus Pro's API and MCP access.