cufilter - Filter emails through Mail::CheckUser

       Rob Brown bbb@cpan.org

       Copyright (c) 2003 Rob Brown bbb@cpan.org.  All rights reserved.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl
       itself.

       $Id: cufilter,v 1.3 2003/09/18 15:36:26 hookbot Exp $

       When email messages are filtered through this program using the procmail settings as outlined in the
       SYNOPSYS, the email address in the "From:" header is passed through Mail::CheckUser to ensure validity.
       If there is a problem with the email address, the "Subject:" header is modified to show which email
       address failed along with the failure reason.  No messages are lost, but it provides an easy way for the
       mail client to organize, sort, or filter based on the subject tweaks.

       Lets say a spammer sends a message with the following headers:

         From: god@heaven.org
         To: you@host.com
         Subject: Happy Pill

       Then the new headers might change to the following:

         From: god@heaven.org
         To: you@host.com
         Subject: [CU!god@heaven.org!DNS failure: SERVFAIL] Happy Pill

       This makes it easy to filter for mail clients.

       This file can be installed into /usr/bin/cufilter and is intended to be utilized through the procmail
       functionality by adding the following lines to your ~/.procmailrc configuration.

         # Filter mail through Mail::CheckUser
         :0f
         | /usr/bin/cufilter

       cufilter - Filter emails through Mail::CheckUser

Mail::CheckUser(3), procmail(1).

perl v5.34.0                                       2022-06-15                                       CUFILTER(1p)

       Add the following lines to your ~/.procmailrc:

         # Filter mail through Mail::CheckUser
         :0f
         | /usr/bin/cufilter