
			SID-MILTER PACKAGE

This directory has the latest open source Sender-ID filter software from
Sendmail, Inc.

Report any bugs to sid-milter-discuss@sourceforge.net.

There is a web site at http://sourceforge.net/projects/sid-milter that is
home for the latest updates.


+--------------+
| INTRODUCTION |
+--------------+

The sid-milter package is an open source implementation of the Sender-ID and
SPF sender authentication systems.

Sender-ID and SPF have both been published by the IETF (RFC4406 and RFC4408,
respectively) as experimental proposals.

This package consists of a library that implements the record parsers needed
to provide the authentication service, and a milter-based filter application
that can plug in to the sendmail MTA to provide that service to sufficiently
recent sendmail and postfix MTAs.

An optional asynchronous resolver library is also provided to work around
limitations of the basic BIND resolver which comes installed on most
systems.


+--------------+
| DEPENDENCIES |
+--------------+

To compile and operate, this package requires the following:

o sendmail v8.13.0 (or later), and libmilter from the same distribution
  (http://www.sendmail.org)


+-----------------------+
| RELATED DOCUMENTATION |
+-----------------------+

Documentation about Sendmail, Inc.'s sender authentication scheme testing
program is available at http://www.sendmail.net.

The man page for sid-filter (the actual filter program) is present in the
sid-filter directory of this source distribution.


+---------------------+
| DIRECTORY STRUCTURE |
+---------------------+

devtools	m4-based build scripts and other data needed to compile
		the package.

libar		An optional thread-safe asynchronous resolver library.

libmarid	A library that implements the syntax and semantics parts of
		the proposed MARID standard for evaluating sender
		authentication.

sid-filter	A milter-based filter application which uses libmarid (and
		optionally libar) to provide Sender-ID service via a
		sendmail MTA and the milter protocol.


+--------------+
| MTA TIMEOUTS |
+--------------+

By default, the MTA is configured to wait up to ten seconds for a response
from a filter before giving up.  When querying remote nameservers
for key and policy data, the filter may not get a response from the
resolver within that time frame, and thus this MTA timeout will occur.
This can cause messages to be rejected, temp-failed or delivered without
verification, depending on the failure mode selected for the filter.

When using the standard resolver library provided with your system, the
DNS timeout cannot be adjusted.  If you encounter this problem, you must
increase the time the MTA waits for replies.  See the documentation in
the sendmail open source distribution (libmilter/README in particular)
for instructions on changing these timeouts.

When using the provided asynchronous resolver library, you can use the
"-T" command line option to change the timeout so that it is shorter than
the MTA timeout.


$Revision: 1.6 $, Last updated $Date: 2008/05/19 17:04:26 $
