What is an MX record?
An MX (Mail Exchanger) record tells sending servers which hosts accept email for a domain and in what priority order. When someone emails you, their server queries your MX records to find where to deliver. A missing or misconfigured MX record means inbound mail cannot be delivered and messages bounce or vanish.
How MX records and priority work
Each MX record pairs a mail host with a priority number. Lower numbers win: a sending server tries the lowest-priority host first and falls back to higher numbers only if it cannot connect. To balance load across equally capable servers, give them the same priority and traffic spreads between them. A typical Google Workspace setup, for example, points to smtp.google.com at priority 1. The MX value must be a hostname with its own A or AAAA record, never an IP address or a CNAME, or delivery breaks.
How to read your MX lookup results
IPeek lists every MX host for the domain with its priority, sorted lowest-first so the preferred server sits at the top. Confirm the hosts match your email provider: Google Workspace, Microsoft 365, your own server or a filtering gateway. Watch for duplicates, typos in hostnames, or trailing dots that signal a misconfigured zone. If the list is empty, the domain has no MX records and cannot receive mail. Cross-check the listed hosts resolve to valid IP addresses before trusting them.
Common MX problems and how to fix them
The most frequent failure is no MX record at all, which forces senders to fall back to the domain's A record or bounce. Pointing an MX at a CNAME violates the spec and many servers reject it, so always target a hostname with a direct A/AAAA record. After switching email providers, stale MX records keep routing mail to the old host until DNS propagates and caches expire. Misordered priorities can send mail to a backup before the primary. Verify changes with a fresh lookup and allow for TTL-based caching.