DIAGNOSTIC PLAYBOOK
Shared sending IP reputation: identify what you control
A shared IP carries traffic from multiple accounts, so its reputation is not a measurement of your domain alone. Investigate your own stream and involve the platform when the evidence points to shared infrastructure.
HealthCheck Email editorial team · · Examples are illustrative
How to investigate
- Record the actual sending IPs and compare failures across time and receiving providers.
- Check your account's authentication, complaints, recipient quality and volume changes.
- Provide message IDs and response samples to the sending platform for investigation of the shared pool.
What this looks like
ILLUSTRATIVE EXAMPLE
Your domain's authentication stays stable while responses change for one shared IP. The provider can compare other traffic and pool-level conditions you cannot see.
A mistake to avoid
A dedicated IP is not an automatic reputation reset. It introduces its own operational and volume requirements.
Keep the result in context
A successful handoff, a delivered event and an inbox placement are different observations. Record the receiving provider, send time, SMTP response and affected stream before comparing results. DNS fixes address authentication or routing; they cannot establish consent or guarantee placement.
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.