What is an MX record? Postal route + free MX checker
An MX record is the postal address for inbound email: when someone writes [email protected], the sender looks up MX to find which mail server should receive it. A free MX checker confirms priorities and hosts are still published before you migrate providers or chase MTA-STS policy lines.
What is an MX record?
An MX (Mail Exchange) record is a DNS record that tells other mail servers where to deliver email for your domain. It maps your domain to one or more mail-server hostnames (not raw IPs) and a preference number. SPF, DKIM, and DMARC protect sending trust; MX is the receive half—without it, inbound mail has nowhere to go.
Priority + hostname (how MX works)
Each MX row has a priority (preference) and a hostname such as aspmx.l.google.com or mail.yourdomain.com. Lower numbers are tried first; higher numbers are backups. Equal priorities can share load. MX must point at a hostname that itself resolves (A/AAAA)—not a CNAME alias and not a bare IP. Providers publish the exact host list and priorities you paste into DNS.
How to check MX (free MX checker)
1) Run the free MX checker on the bare domain. 2) Confirm at least one MX host is listed with a priority. 3) Read whether hosts match your real provider (Google Workspace, Microsoft 365, Hostinger, custom). 4) Spot leftovers from a retired ESP. 5) If you publish MTA-STS, compare policy mx: lines to the live list. 6) After any zone edit, re-check; MX rows are easy to drop in panel “cleanups.”
What CrowWake checks
We resolve MX for your domain and list priorities plus hosts. Healthy exchangers → ok. Zero MX → fail (unless you intentionally receive no mail—CrowWake still flags empty so a silent wipe is visible). The free MX checker uses the same public lookup with no login. CrowWake does not open an SMTP session or prove mailbox delivery in v1. For the repeat “watch this hourly” job, see the dedicated MX monitoring guide.
MX record vs MX monitoring
This guide is the definition and publish/triage job: what an MX record is, how priorities work, and how to check MX with a free MX checker. MX monitoring is the hourly rooster—catch a wiped exchanger, leftover hosts from a retired ESP, or a migration that never put Google/Microsoft back. Both use the same free checker; CrowWake just repeats the pulse.
Why it matters
Without MX, people cannot email [email protected]—messages bounce or queue. Agencies juggling many client zones hit this after a cleanup that deleted the wrong rows, or a provider switch that never published the new hosts. MTA-STS also depends on accurate mx: lines matching live MX.
What “good enough” looks like
MX pointing at your real inbound provider. Priorities make sense (primary lower preference number, backups higher). No leftover MX from a host you retired. If the domain is send-only, decide consciously (null MX is a choice)—CrowWake still crows on empty so accidental wipes do not hide.
Publish checklist (order matters)
1) Open your email provider’s MX setup guide and copy the hostnames + priorities. 2) Publish those MX rows at the apex (or the host they specify). 3) Run the free MX checker and confirm the live list. 4) Remove retired exchangers. 5) If you use MTA-STS, align policy mx: lines (free MTA-STS checker). 6) Add the domain so CrowWake crows if MX disappears.
If CrowWake crows
Empty MX → restore hosts from your provider’s docs, then re-run the free MX checker. Wrong leftovers → delete retired exchangers; keep only the current set. Mid-migration → publish the new provider’s MX before removing the old if you still need dual receive. After DNS changes, give caches a few minutes, then confirm CrowWake goes green.
Watch this on CrowWake
Add the domain, leave the boxes checked, and the flock will crow when this drifts.
Or try the free MX record / MX checker checker with no login.
Deep dive: MX monitoring — watch inbound exchangers so a silent wipe or leftover host crows early, with the same free MX checker.
The free MX checker lists live priorities and hosts. Pair with email authentication monitoring, what is email authentication, SPF monitoring, DKIM monitoring, DMARC monitoring, and MTA-STS monitoring.