DMARC report lists ten sending IPs, I can't tell which are ours
Per-source breakdowns in DMARC reports map each IP to a service. That surfaces shadow IT sending in your name.
support/email-aflevering/dmarc-per-source-breakdownsteps: 4
Try this first
- Use a DMARC aggregator (dmarcian, Postmark) to visualise reports
- Look up the PTR record per IP, that usually reveals the provider
- Match IPs to your known services (CRM, ESP, ticketing)
- Unknown sources: block or bring under DKIM/SPF
When to bring us in
If you can't trace an IP, don't jump to p=reject, identify first.
See also
- Our emails land in spam for some recipientsAlmost always an SPF, DKIM, or DMARC setting that is wrong or missing, or a sender name that mimics a well-known brand.
- Someone reports receiving phishing emails "from us"Read: spoofing. Someone is abusing your sender name, not necessarily your actual mailbox.
- An email bounces (NDR): delivery failedThe NDR text usually states the exact reason. Reading it is step one.
None of the above fits?
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