![[LWN Logo]](/images/lwn.banner.gif)
From: Jochen Wiedmann <joe@ispsoft.de>
Subject: COMMERCIAL: IspMailGate (Virus scanning and PGP support for sendmail)
Date: Wed, 29 Apr 1998 12:00:15 GMT
-----BEGIN PGP SIGNED MESSAGE-----
Hello,
We'd like to announce the first release of the
IspMailGate
system, a general-purpose email filter integrated into sendmail,
written in Perl and based on the MIME-tools.
WARNING:
========
This is an alpha release of a fairly complex application.
One must not expect easy installation or running out of the box,
although we did our best to make things as easy as possible. This
release is mainly for detecting possible problems that we aren't
yet aware of.
OVERVIEW:
=========
The main idea of IspMailGate is as follows: Two sites that are
exchanging emails relatively frequently (for example a company's
headquarter and an external branch) are both running email servers
based on sendmail. Thus it is possible to modify emails on the
sending site and restore the original on the receiving site in a
completely transparent manner. For example one could compress and
encrypt emails before they reach the Internet, but decompress and
decrypt them when they leave the Internet and before they are
delivered to the user. (Yes, we know that PPTP or IPSEC are a
simpler and more general approach, but ours is cheaper and offers
additional possibilities.)
Of course you are not bound to the two-sites design, the virus
scanner is an excellent example where its useful to install
IspMailGate on a single site.
The scheme of an IspMailGate installation is as follows:
------------------ +--------------+
\ \ 1.) | | 4.) Mail being
\ Mail (incoming \ -----> | sendmail | delivered
\ or outgoing) \ | |
\ \ | | -------------->
------------------ +--------------+
| ^
2.) Mail being passed | | 3.) Mail being passed
to IspMailGate for | | back to sendmail
filtering | | for delivery
y |
+-------------+
| |
| IspMailGate |
| |
+-------------+
Which emails are passed to IspMailGate is configurable with a
sendmail map. For example you might use the following map:
joe@othercompany.com :ispmailgate
@friends.org :ispmailgate
.company.com :ispmailgate
The above means that mails would be fed into IspMailGate, if the
recipients are joe@othercompany.com, *@friends.org or *@*.company.com.
Other emails would be delivered in the usual way, without performance
penalty.
Note, that specifically the @domain syntax is well designed for
Internet providers that like to offer virus scanning as a paid
service to their customers.
WHAT IT DOES:
=============
Filtering an email can mean arbitrary things, filters are implemented
as modules that are called by the IspMailGate system. The filter API
is quite simple, so it is easy to implement own modules or customize
them for your needs. Currently available modules are:
- Abstract base classes for deriving modules from them.
- A filter doing automatic compression and decompression.
- A PGP filter doing automatic encryption and decryption
- A virus scanning module; needs an external virus scanner,
for example VirusX from http://www.antivir.de
All these modules are based on external binaries (for example
tar and gzip for compression, pgp for the PGP module, archive
deflaters like unzip, arj, ... for the virus scanner). The compression
and PGP modules are designed for use of IspMailGate on two ends, for
example a companies headquarter and a local branch. The sending site
does compression and encryption, the receiving site does decompression
and decryption. However, it should be easy to adapt the PGP module
for communication with AK-mail or other Email clients supporting
PGP, so that one can easily encrypt or decrypt mails to or from single
persons.
Other modules that might soon follow are:
- PGP signing
- server sided SPAM detection
On the TODO list is a daemon version (99% complete) and a small C
wrapper for integration into sendmail (there are open problems with
Perl's I/O and read hanging) which will perform much better than the
current version.
DOWNLOADING:
============
The program is available from any CPAN mirror, for example the
upload site
ftp://franz.ww.tu-berlin.de/pub
file: $CPAN/authors/id/JWIED/Mail-ispmailgate-1.000.tar.gz
size: 47950 bytes
md5: 41260c5ceb546e9eca1f4a420b4be20b
THANKS:
=======
We'd like to express our special thanks to
- Eryq <eryq@zeegee.com>, author of the MIME-tools
- Graham Barr <barr@pobox.com> for the IO modules which made
implementing streams incredibly flexible
- the MakeMaker authors <makemaker@franz.ww.tu-berlin.de> for
an excellent help in installation of applications
LICENSE:
========
Sorry, but IspMailGate is not completely free. Anyone's invited to
try the current release, but it will remain free for private use
or use in educational and non-profit organizations only. We'd like
to bill a fee around 200$ for a future release, whenever we think
it's really running without problems. See the LICENSE file for
details.
AUTHORS:
========
Copyright (C) 1998 Amar Subramanian
Grundstr. 32
72810 Gomaringen
Germany
Email: amar@neckar-alb.de
Phone: +49 7072 920696
and Jochen Wiedmann
Am Eisteich 9
72555 Metzingen
Germany
Email: joe@ispsoft.de
Phone: +49 7123 14887
All Rights Reserved.
Thanks for reading so far,
Amar and Jochen
- --
Jochen Wiedmann joe@ispsoft.de
Linux - Just do it! 07123 14887
- --
This article has been digitally signed by the moderator, using PGP.
http://www.iki.fi/mjr/cola-public-key.asc has PGP key for validating signature.
Send submissions for comp.os.linux.announce to: linux-announce@news.ornl.gov
PLEASE remember a short description of the software and the LOCATION.
This group is archived at http://www.iki.fi/mjr/linux/cola.html
-----BEGIN PGP SIGNATURE-----
Version: 2.6.3ia
Charset: latin1
iQCVAgUBNUcWT1rUI/eHXJZ5AQHJEQQAhM3MrOCpDgKHCixVAyHrdj1IwY/OEbPZ
VraEiCLCyTK6NP10rWyuE4hxNfZNAn3baER6Y5cXK4XuNidgNwO4Hd5Dp0VB1D25
In7+3Xdl3U9WrkTGR43YJy2AGQUsL2o6cvZ66qYnzkV1C2sqwoa+5MLoTP2iQ44m
1nL/vG2v8TY=
=6XGe
-----END PGP SIGNATURE-----