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.\" ========================================================================
.\"
.IX Title "CUFILTER 1p"
.TH CUFILTER 1p "2022-06-15" "perl v5.34.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
cufilter \- Filter emails through Mail::CheckUser
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
Add the following lines to your ~/.procmailrc:
.PP
.Vb 3
\&  # Filter mail through Mail::CheckUser
\&  :0f
\&  | /usr/bin/cufilter
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
When email messages are filtered through this program
using the procmail settings as outlined in the \s-1SYNOPSYS,\s0
the email address in the \*(L"From:\*(R" header is passed through
Mail::CheckUser to ensure validity.  If there is a problem
with the email address, the \*(L"Subject:\*(R" 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.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
Lets say a spammer sends a message with the following headers:
.PP
.Vb 3
\&  From: god@heaven.org
\&  To: you@host.com
\&  Subject: Happy Pill
.Ve
.PP
Then the new headers might change to the following:
.PP
.Vb 3
\&  From: god@heaven.org
\&  To: you@host.com
\&  Subject: [CU!god@heaven.org!DNS failure: SERVFAIL] Happy Pill
.Ve
.PP
This makes it easy to filter for mail clients.
.SH "INSTALL"
.IX Header "INSTALL"
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.
.PP
.Vb 3
\&  # Filter mail through Mail::CheckUser
\&  :0f
\&  | /usr/bin/cufilter
.Ve
.SH "AUTHORS"
.IX Header "AUTHORS"
Rob Brown bbb@cpan.org
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright (c) 2003 Rob Brown bbb@cpan.org.
All rights reserved.
.PP
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
.PP
\&\f(CW$Id:\fR cufilter,v 1.3 2003/09/18 15:36:26 hookbot Exp $
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBMail::CheckUser\fR\|(3),
\&\fBprocmail\fR\|(1).