Re: Restrictive SMTP server

[Gunnar Wolf <gwolf@gwolf.org>]

Daniel Ruoso dijo [Sat, Mar 12, 2005 at 04:18:06PM -0300]:
> I'm with a problem about sending emails @debian.org. My ESP (email
> service provider) has a restrictive rule about sending emails with a
> >From header different of the account you actually have.
> 
> This wouldn't be a problem, as I could set up a mail server in my
> machine, but I am in a DSL network which is completely blacklisted due
> to spammers.
> 
> The fact is that I am unable to send emails with my debian.org address.
> Does someone has some idea of how can I fix that?

Hi,

Many suggestions have already been posted - I have your same
situation, but have been working correctly with it for over one
year. What I do is:

- I deliver SMTP to the smarthost 127.0.0.1:10025
- At 127.0.0.1:10025, I have a ProtoWrap agent invoked with the script
  shown below
- ProtoWrap changes the envelope and hands it over to my ISP's MTA

What is ProtoWrap [1]? A simple daemon I wrote a long time ago made to be
a generic proxy for line-oriented protocols. It works fine, but I
don't know if it is usable/useful enough for packaging it. 

Ok, and here is the invoking script:

-----
#!/usr/bin/perl -w
use strict;
use ProtoWrap;

my $wrap;
$wrap = ProtoWrap->new(standalone => 0,
		       destAddr => 'smtp.prodigy.net.mx',
		       destPort => 25,
		       destType => 'ip',
		       logLevel => 2,
		       testLine => \&rewriteEnvelope);
$wrap->startServer or warn "Can't start server: ",$_->getProp;

sub rewriteEnvelope {
    my ($self,$line,$socket,$who);
    $self = shift;
    $line = shift;
    $socket = shift;
    $who = shift;

    unless (ref $line) {
	warn "No es una referencia: $line";
	return 1;
    }

    if ($$line =~ /^mail from:/i) {
	$$line = 'MAIL FROM: gwolf@prodigy.net.mx';
    }
    return 1;
}
-----

You will find that it might be too simplistic. In fact, it can
(seldom) lead to errors - Lets say I want to say I got a mail from
your address... You will get it differently:

MAIL FROM: gwolf@prodigy.net.mx

...But anyway, it works quite nicely.

Greetings,

[1] http://www.gwolf.org/seguridad/wrap/

-- 
Gunnar Wolf - gwolf@gwolf.org - (+52-55)1451-2244 / 5554-9450
PGP key 1024D/8BB527AF 2001-10-23
Fingerprint: 0C79 D2D1 2C4E 9CE4 5973  F800 D80E F35A 8BB5 27AF