Re: SRS sendmail integration

On Thu, 25 Mar 2004, Kees Cook wrote:

> Is there a "working" m4 hack for joe-job protection?  It sounded like 
> people had one, but I couldn't piece it together from the archives.

I am not sure which kind of forgery "joe-job" refers to.  However, the
m4 hack discussed here signs your outgoing mail so that you can recognize
forged bounces, as well as rewriting forwarded mail so that SPF is
satisfied.  A working, fairly well tested (5 production machines)
version using a Python port of SRS and m4 sendmail hack can be found at:

  http://bmsi.com/python/pysrs.html

Links to Perl and C versions of SRS as well as Marks instructions 
for manually hacking sendmail.cf are at

  http://spf.pobox.com/srs.html

SPF provides a way to let others detect forged email claiming to be from
you.  However, only a tiny percentage of MTAs check it so far.  Even so,
it stops a signficant portion of spam on my system (especially since I
cheat and reject neutral results for aol.com).  If nothing else, it
provides a very flexible way to specify where your own mail legitimately
comes from, so I don't get any more spam from my colleagues. :-)

  http://spf.pobox.com

A python milter that rejects unsigned bounces that reach the DATA phase
and checks SPF is at:

  http://bmsi.com/python/milter.html

The SPF download page has links to a C SPF checking milter and Perl
C, and Python libraries for checking SPF.

-- 
			Stuart D. Gathman <[email protected]>
      Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
      "Very few of our customers are going to have a pure Unix
      or pure Windows environment." - Dennis Oldroyd, Microsoft Corporation