I am familiar with customizing the sendmail delivery part, with
procmail or your own delivery agent.

The part I am curious about is the other side. Is there anyway (other
than rewriting sendmail) to place a preprocessing filter ahead of
sendmail? The filter in question will look at the From and To headers
and use pgp to selectively encrypt some of the mail messages.

Is there something already out there which does this?

-Ramon F Herrera

Ramon F Herrera wrote:
> I am familiar with customizing the sendmail delivery part, with
> procmail or your own delivery agent.
>
> The part I am curious about is the other side. Is there anyway (other
> than rewriting sendmail) to place a preprocessing filter ahead of
> sendmail? The filter in question will look at the From and To headers
> and use pgp to selectively encrypt some of the mail messages.

Hunh?

Given that pgp/gpg is rather easy to use from a MUA, I'm not sure
why you'd want to do this..

>
> Is there something already out there which does this?

Yes. Sendmail, mimedefang, spamassassin.

base60 wrote:
> Ramon F Herrera wrote:
> > I am familiar with customizing the sendmail delivery part, with
> > procmail or your own delivery agent.
> >
> > The part I am curious about is the other side. Is there anyway (other
> > than rewriting sendmail) to place a preprocessing filter ahead of
> > sendmail? The filter in question will look at the From and To headers
> > and use pgp to selectively encrypt some of the mail messages.
>
> Hunh?
>
> Given that pgp/gpg is rather easy to use from a MUA, I'm not sure
> why you'd want to do this..
>

I am just checking my options, since I have been away from sendmail for
a while.

Additionally, current users are using pgp/gpg from their MUAs, but
management wants to enforce it transparently.

Thanks,

-Ramon

"Ramon F Herrera" <ramon@conexus.net> writes:

> I am familiar with customizing the sendmail delivery part, with
> procmail or your own delivery agent.
>
> The part I am curious about is the other side. Is there anyway (other
> than rewriting sendmail) to place a preprocessing filter ahead of
> sendmail? The filter in question will look at the From and To headers
> and use pgp to selectively encrypt some of the mail messages.
>
> Is there something already out there which does this?

It can be done relatively easily via milter. You can use perl based GPL
licenced MIMEDefang milter as test ground for rewriting messages body.
http://www.mimedefang.org/

Milters are consulted during incoming SMTP session. It makes their
deployment "peak load sensivitive".

There are other possible rewriting (signing/encrypting) methods allowing
but "throughput averaging" they may be trickier to debug and less
general.

--
[pl2en: Andrew] Andrzej Adam Filip : anfi@priv.onet.pl : anfi@xl.wp.pl