Backscatter is unwanted bounce mail sent to forged sender addresses. Learn why it happens and how to prevent your domain from being involved.
Backscatter email is misdirected bounce or auto-reply mail that gets sent to a forged sender address. It happens when spammers spoof a From address and the receiving system sends failure notices to the impersonated sender instead of rejecting the mail properly.
Backscatter creates noise, can harm reputation, and wastes server resources. It also confuses recipients who receive bounce messages for emails they never sent.
The best prevention is rejecting suspicious mail during the SMTP transaction rather than accepting and later bouncing it. Strong authentication (SPF, DKIM, DMARC) also reduces successful spoofing and the resulting backscatter.