we want to improve our mailing lists by handling all the bounces we get. As I saw there are different approaches. One checks the badmail folder in IIS mailroot folder. Others check a email account using pop3 to get the bounces.

Our setup is an exchange server behind a IIS SMTP server. We send from different servers (out) and different addresses. But incoming is all the same server.

What software can help us to easily handle the bounces? I do not want a tool, that removes all emails from the server (pop3), as I imagine to scan employees accounts as well as automatic accounts. The tool should allow actions to be taken (call a batchfile, or call a URL to do something with the address bounced.

What about the difference between the badmail folder and the Nondelivery Emails? Do both cover all bounces or just combined?

Thank you!


First of all, badmail and bounces capture different problems, so yes, you need both.

  • The badmail folder contains mails that IIS could not send at all (i.e. they were rejected by the SMTP server IIS tried to pass on the mail).
  • Bounces happen if IIS successfully passed on the mail to another server, but the delivery failed later on in the chain of SMTP servers. In that case, STMP server will (usually, if they feel like it, etc.) send a bounce back to the original sender to tell them about it.

As to handling them, that greatly depends on what you want to do based on them.

First of all, use a special sender address for your mailing lists (the address that IIS gives in MAIL FROM, should be configurable). That's where bounces go. If you have a separate address per mailing list, you can easily separat bounces for mailing list posts from other bounces caused by regular user mail.

Then you can grab these by POP3, and process them. Actual processing could be done by some kind of script (Perl for example has nice libraries for picking apart emails). In the simplest case you could extract the failed email address, and remove/deactivate it from your mailing list if it failed a few times.

I'm not aware of special software to do this, but there may be some. Maybe your mailing list sw can do this?

  • Thank you for your reply. Can you refine "contains mails that IIS could not send at all". If I check our badmailfolder, it contains non-deliverable notifications for emails send from unknown (external) addresses to non existent internal email addresses. If I use listnanny to parse them the "bounced emailadress" is always an internal address (=one of our domain). How is that possible? where is the sense of this? – kcode Sep 18 '09 at 13:05
  • I know little about IIS, just about mail sw in general, so most of my advice was meant as general email advice, sorry. To address your question: "non-deliverable notifications for emails from unknown (external) addresses to non existent internal addresses" sounds like IIS received a bogus bounce, i.e. a bounce for a mail you never sent. This is usually caused by spam that uses you as a forged sender address (spam frequently has a forged sender address) – sleske Sep 23 '09 at 0:36

You might be able to write something using http://www.listnanny.net/

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