Email is business-critical infrastructure, but it rarely gets the same monitoring attention as the website. MX records are the routing layer: they tell the internet which servers accept mail for your domain.
What MX records do
Each MX record has a priority (lower number = preferred). Mail servers try higher-priority hosts first. If your MX points to the wrong provider — or disappears — inbound mail bounces or vanishes into a black hole.
Changes that break mail silently
- Migrating from one host to another without updating all MX entries
- Accidentally deleting MX during a DNS cleanup
- Pointing MX to a decommissioned server after a merger
- Typos in priority values (mail still "works" but fails over incorrectly)
Baseline and compare
Capture your current MX configuration with the free MX checker. Store that as the expected state. Alert when:
- MX hosts change
- Priorities reorder unexpectedly
- Records disappear entirely
Confirm before you panic
Some providers use multiple MX records for redundancy. A change might be intentional (Microsoft 365 migration, for example). UpMonix lets you confirm a new MX baseline after planned work so future unauthorized changes still trigger alerts.
Pair MX monitoring with domain and DNS checks on the same domain monitor for a complete picture of mail routing health.