Your server has to support procmail in order to use this. Ask your hosting provider if you are not sure. You will need to create a file named “.procmailrc” in the home directory (not your public html directory but one level up from that) on your server for the specified domain where the mailing list plugin is running and remember to CHMOD the file to 0755 in order for it to be executable. Put the following code into the “.procmailrc” file.
:0 * ^TO_bounce@domain.com |/path/to/your/cgi-bin/wpmlbounce.cgi
…where “firstname.lastname@example.org” should be replaced with the email alias you wish to use. The path should also be the actual, correct path to your CGI-bin directory.
If the above doesn’t work, contact your hosting provider and ask them to create an alias for you and provide them with an absolute path to your “wpmlbounce.cgi” script which you previously configured and uploaded. They might need to edit the “/etc/aliases/” file on the server.