Editing Email spam (section)

===Backscatter spam===
{{Main|Backscatter (email)}}
Backscatter is a side-effect of email spam, [[computer viruses|viruses]], and [[computer worm|worms]]. It happens when email servers are misconfigured to send a bogus [[bounce message]] to the [[envelope sender]] when rejecting or quarantining email (rather than simply rejecting the attempt to send the message).

If the sender's address was forged, then the bounce may go to an innocent party. Since these messages were not solicited by the recipients, are substantially similar to each other, and are delivered in bulk quantities, they qualify as unsolicited bulk email or spam. As such, systems that generate email backscatter can end up being listed on various [[DNSBL]]s and be in violation of [[internet service provider]]s' [[Terms of Service]].