DIAGNOSTIC PLAYBOOK
Build an email sender inventory before changing policy
A sender inventory connects each legitimate mail stream to an owner, platform and authenticated identity. It turns an unfamiliar report entry into a question you can resolve before changing domain policy.
HealthCheck Email editorial team · · Examples are illustrative
How to investigate
- List mailbox, marketing, billing, support, application and device-generated mail with a responsible owner for each.
- Send a sample from each path and record its From, envelope domain, DKIM domain and selector.
- Compare the list with aggregate reports and investigate unmatched sources before approval.
What this looks like
ILLUSTRATIVE EXAMPLE
The finance team uses a billing tool nobody included in the original DNS checklist. Its sample reveals an unaligned stream before stronger enforcement is published.
A mistake to avoid
An IP list alone is not a complete inventory. Shared services and changing ranges make platform and identity ownership essential.
Keep the result in context
A monitoring routine needs an owner, a baseline and a response to a meaningful change. Keep the sender inventory and approved DNS configuration alongside incident notes. HealthCheck Email supplies checks, history and supported alerts; publishing DNS changes and administering mail systems remain with your team.
Take the next step
Use the related check to gather evidence, then compare it with the affected message or service. Keep the result and time with your notes so a later change can be distinguished from the original problem.
Sources and further reading
The protocol references below explain the underlying behavior. Your sending or DNS provider supplies the account-specific settings for its service.