----------------------------------------------------------------------
		    SENDMAIL CONFIRMATION SYSTEM (SMC)
----------------------------------------------------------------------

Sendmail Confirmation System (SMC) is an software application designed
to significantly reduce the amount of SPAM/UCE (junk-mail) you receive.
SMC uses a dynamic local and DNS based remote "whitelists" (for
known/trusted senders), DNS based "blacklists" (for undesired senders),
and an original autoconfirmation system (for unknown, but legitimate
senders). In additional SMC has a set of useful features which allows
to preserve mail recipients from dangerous message attachments, HTML
includes. SMC is an Sendmail milter (plugin), which stops the junk-mail
without receiving one.

NOTE: SMC is developed and tested on Linux only. Supporting of other
operating systems is planned.

----------------------------------------------------------------------
			    SMC ALGORYTHMS
----------------------------------------------------------------------
NOTE: Please see the both of COPYING section below and the file COPYING
in this directory for full copyright information.
----------------------------------------------------------------------

SMC uses 3 original algorithms, one of which is "Check relay by NS"
simulates a dynamical whitelist and will always accept the messages
from mail systems satisfying to following conditions:

1) Mail domain name (the host part of the sender's e-mail address) must
   have an MX records;
2) Mail domain name and the connection host address must be resolved;
3) Connection host must be listed at the one of nameservers which hold
   the sender's mail domain name.

The second from the developed algorithms is a "check delays" algorithm
which is based on statistical check of delivery delays, generated by a
[tempfail] return code, that allows to exclude a direct receiving of a
mail, which not passed through the standard mail server.

NOTE: Using this feature the delivery of the mail from unknown, but
legitimate senders will be delayed for a count of 5-minutes checks,
which setted by the "maxcount" configuration parameter.

And the third of original algorithms is "autoconfirmation" algorithm:
The sender of a "mail contact" (sender-recipient pair) means as
authenticated (whitelisted) if the filters statistics module has
registered the both of a sended forward (request) and a recieved
backward (reply) messages of this contact. The messages from the such
authenticated senders will never be delayed by the previos "check delay"
algorithm.

----------------------------------------------------------------------
			DNS BASED LISTS SUPPORT
----------------------------------------------------------------------

SMC has the ability to look up connecting IP addresses against DNS-based
blacklists, whitelists and dialup users lists. These lists are described
in smc-milter.policy file in following format:

Id:	[rbl] - DNS black/white list, [dul] - Dialup users list.
Flag:	[NO]  - Accept mail, [YES] - Reject mail.

Id	Flag	Check address			Info address
-----------------------------------------------------------------------
rbl	NO	query.bondedsender.org		http://bondedsender.org
rbl	YES	blackholes.mail-abuse.org	http://mail-abuse.org
rbl	YES	relays.mail-abuse.org		http://mail-abuse.org
dul	YES	dialups.mail-abuse.org		http://mail-abuse.org/dul

NOTE: The rules of policy are executed sequentially.

----------------------------------------------------------------------
			    SMC EXTENSIONS
----------------------------------------------------------------------

SMC has 2 additional important features which allows to preserve mail
recipients from dangerous message attachments and HTML includes:

1) If the SMC configuration file parameter "extrename" is set to "yes"
   dangerous message attachmets will be renamed in following manner:

   filename....pif	will be renamed to	filename....pi_
   filename....exe	will be renamed to	filename....ex_
   filename....vbs	will be renamed to	filename....vb_

   e.t.c.

2) If the SMC configuration file parameter "cleanhtml" is set to "yes"
   dangerous HTML includes, such as a various scripts, embedded objects
   e.t.c. will be removed from receiving messages.

----------------------------------------------------------------------
			  SMC CONFIGURATION
----------------------------------------------------------------------

Please type "smc-milter -h" in SMC programs directory to see all of
configuration options.

----------------------------------------------------------------------
			      WARNING
----------------------------------------------------------------------

THE AUTHOR DOES NOT ACCEPT ANY RESPONSIBLITY FOR MAIL REJECTED OR
POSSIBLE LOSS OF BUSINESSS THROUGH THE USE OF THIS SOFTWARE. PLEASE
REVIEW BOTH THIS DOCUMENT AND THE SOURCE CODE. USE AT YOUR OWN RISK.

----------------------------------------------------------------------
			      COPYING
----------------------------------------------------------------------

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

Please see the file COPYING in this directory for full copyright
information.

----------------------------------------------------------------------

For more information, visit the SMC homepage: <http://milter.sf.net>

----------------------------------------------------------------------
			      TRADEMARKS
----------------------------------------------------------------------
Linux is a trademark of Linus Torvalds.
Sendmail is a trademark of Sendmail, Inc.
