Our DKIM-signed mail is being reused by a spammer
In a DKIM replay attack, someone grabs a legit signed message and blasts it widely. Your domain gets blamed.
Try this first
- 1Check Postmaster Tools and SNDS for spikes you didn't send
- 2Limit DKIM signing validity with the x= tag
- 3Do NOT use the l= tag, sign the full body
- 4Rotate the selector if the replay is ongoing
When to bring us in
If reputation tanks from replay, get the mail provider to file abuse with receivers.
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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