We are getting many reports of mail servers under heavy load because of SPAM backscatter. This happens when a spammer uses a company’s email address to forge the “FROM” field in the email. When mail servers get these spam emails and reject them because they are sent to a user that doesn’t exist, the SPAM targeted mail server will send a bounce back message to the forged “FROM” field. Now as you might imagine, when a spammer sends out over a million emails it’s very likely that many of those will go to addresses that no longer exist, and innocent company in the “FROM” field gets blasted by thousands of bounce backs.
What can we do about this though? Unfortunately if you’re the one getting the backscatter, not a whole lot. However, you can help to prevent backscatter for others. We recommend that email servers be configured to REJECT bad email during the initial transaction instead of accepting it and creating a bounce back reply. Also consider not using “out of office” email replies. This also creates backscatter when the vacationed user receives spam. This could also land you on a spam blacklist, if whoever got the backscatter happened to report your mail server as a backscatter sender.