Checking email Return-path to fight spam

[demouser]

Not really php, more of a mail server issue....

A customer fills out a web form and emails it to us. Unfortunately, the form submission address has been harvested in the past and thus gets us spam as well. Hiding the email address better is a separate issue. Can't simply change the address since it's widely published in catalogs.

Legitimate form submissions have

Return-path: <[e-mail]>

as the first line of the header.

Any way to weed out and dump the emails from this address that have a different return-path? I only need this for the one email that is used for forms, not all of them. Email filtering and Spam-Assassin are site-wide.

Is there a solution to this or is this in the domain of the web host's mailserver?

Thanks!

[NogDog]

I would think you could do it with PHP using the IMAP/POP3 functions, but it would probably be more efficient to do it something on the mail server that could filter each message as it arrives. (What that "something" might be, I don't happen to know off the top of my head, though.)

[bradgrafelman]

Well, if you are using Postfix, you can have your mail server automatically send all emails off to a PHP script for parsing, as mentioned here.

You could check for the appropriate header (and anything else you wanted) and then use PHP's mail() function to send the actual e-mail on to an internal mailbox (keep this mailbox name a secret so that spammers can't directly mail to it).