December 15th, 2008

Stop the Backscatter Spam with a Custom Filter

We recently talked about the problems created by backscatter or bounce back spam.  I.e. the pain caused by getting lots of "delivery failure" messages for messages that you never sent, but which arrive at your door anyway. One of the solutions we have provided for dealing with backscatter, if you have this problem, is to create a custom email filter in your LuxSci WebMail interface that will delete or save all bounce messages.  While this works well, it also has a drawback.

If you are using LuxSci’s custom filters to save or delete all messages from "mailer daemons", then you will not see bounce back messages resulting from messages that you yourself have sent legitimately.  This is usually OK, but if you mistype a critical email address, you might never know that a very important email was not delivered. That could be a problem.

New BackScatter Filter

To at least partially address this issue, LuxSci has introduced a new "backscatter" filter in its custom email filtering tool.  This filter matches all bounce back/non-delivery messages that were not generated by your WebMail or outbound SMTP servers.  As such, it will effectively block the backscatter while at the same time allowing most of the real delivery failure messages to make it back to you.

Of course, even this filter has its limits. It will treat legitimate bounces as "backscatter" in cases where:

  • You are not sending the message from LuxSci’s email or WebMail servers.
  • The message sent is in fact accepted by the recipient’s servers, but later bounces back from their system for some reason, without direct reference to the fact that it was received from LuxSci.
  • You are sending messages automatically as a result of received messages (i.e. forwards, auto-replies, notifications, etc.) and these auto-generated messages bounce.

So, even if you are using this filter, we do not recommend deleting your backscatter outright.  The ideal thing to do is have a copy of it saved in a folder for a limited time and then auto-delete it after a period of time.  This is easy to set up with our folder management tools.

One Response to “Stop the Backscatter Spam with a Custom Filter”

  1. Bounce Back & BackScatter Spam - “Who Stole My Email Address”? | LuxSci FYI Says:

    […] messages that you actually sent.   5) Filter backscatter email explicitly. LuxSci has a special custom email filter designed to filter messages from "mailer-daemons" that are not from LuxSci’s […]

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