How do I block backscatter?

For a detailed explanation about what backscatter is, please see this article.

How to turn on the backscatter filter

  1. Login to the SEAS Accounts Management page.
  2. Click on the Spam Blocker, Blocked/Allowed Addresses link on the left navigation bar.
  3. Scroll down to the backscatter filter section and select Yes.
  4. Click Update Email Filters.

How the backscatter filter works

The backscatter filter will not block all backscatter, but it will greatly reduce the number that show up in your inbox. All blocked backscatter will be sent to your spam folder.

A legitimate bounce is virtually indistinguishable from a backscatter bounce, but if you receive 200 bounces at once they are probably all backscatter, and if you receive only one bounce it is probably "real".

The filter divides time into three 15 minute chunks and counts the number of bounces you receive in each chunk. In any given sequence of three chunks, the first three bounces you receive go into your inbox, and the rest go into your spam folder.

If you send a message to a long list of addresses and more than three of them bounce, you'll only see the first three bounces in your inbox. If you do want to see all the bounces, you can either look in your spam folder, or turn off the backscatter filter before you send to your list.

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