MX records
MX records show which mail exchangers are published for receiving email for a domain.
Why it is observed
Mail routing is visible infrastructure evidence
Why it matters
MX records provide routing context for email-provider movement and Mail trust posture when read with SPF and DMARC evidence.
What visible change may mean
A change may reflect mail-provider migration, filtering or routing changes, reseller configuration, cleanup or maintenance.
Interpretation limits
Mail routing does not describe the whole mail control environment
MX posture describes visible public routing evidence. It does not establish active use, delivery quality, sender authentication effectiveness, organisational maturity or compliance. Provider attribution remains an inference.
What .auDO observes
The published mail-exchanger set
.auDO records public MX answers and their query outcomes. Within mail-posture/v1, this evidence contributes a bounded MX posture of visible, null_mx, not_observed or indeterminate. Email-provider classification remains a separate best-effort inference.
Technical fields
Common retained observations
Mail-exchanger change
Where to use this evidence
Use MX for routing context and Mail trust posture
Email provider State remains the owner for provider and routing inference. Mail trust posture owns the combined MX, SPF and DMARC aggregate interpretation.
Related concept
What MX records reveal
Related signals