Home page logo
/

basics logo Security Basics mailing list archives

Re: Filtering SPAM with Linux
From: Rajeev Kumar <rajeev () rajeevnet com>
Date: Tue, 27 Apr 2004 14:04:10 -0400

Ivan,
You need to setup a mail server on your proxy box which will collect all incoming mail at port 25 and then apply SPAM filter there.

One practical solution could be, install postfix (http://www.postfix.org) as a mailgateway, postfix has lots of anti-spam setup procedure and you can follow some nice websites/papers on this setup. After your mail gateway, you can deliver mails to next hop (i.e your MS exchange server).
Look for this sites on how to setup postfix with antispam.

http://www.advosys.ca/papers/postfix-filtering.html
http://www.securitysage.com/guides/postfix_uce.html
http://jimsun.linxnet.com//misc/postfix-anti-UCE.txt
http://www.mengwong.com/misc/postfix-uce-guide.txt
http://www.postfix.org/uce.html


Also you can incorporate some third party spam filters such as Spamassassin (Open source). Sophos Puremessage (Commercial , bit costly anti-spam filter but works very nicely)

Similar can be done with sendmail also, but I would prefer postfix which is lot better to administer than sendmail.

Hope this helps.

Rajeev

ivan.hernandez () globalsis com ar wrote:
Hello. I have a box with linux that is acting as NAT and Firewall (also
cache with squid and reverse proxy with pound).
I have an internal MS Exchange server that goes to internet via NAT, and
i dont have any chance of removing it, but i would like to filter the
incoming traffic to remove spam.
My net looks something like this:


INTERNET <---> x.x.x.x LINUX BOX 10.1.20.100 <---> 10.1.20.1 MS Exchange

What can i use in the linux box? I have found things like MessageWall and
so, but i need better recomendations from people that already doed it.

Thanks!!
Ivan Hernandez

---------------------------------------------------------------------------
Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off
any course! All of our class sizes are guaranteed to be 10 students or less
to facilitate one-on-one interaction with one of our expert instructors.
Attend a course taught by an expert instructor with years of in-the-field
pen testing experience in our state of the art hacking lab. Master the skills
of an Ethical Hacker to better assess the security of your organization.
Visit us at:
http://www.infosecinstitute.com/courses/ethical_hacking_training.html
----------------------------------------------------------------------------

--
____________________________________________________________________
        Rajeev Kumar (rajeev () rajeevnet com)
                http://www.rajeevnet.com
-- PGP PUBLIC KEY -- http://www.rajeevnet.com/crypto/mypubkey
____________________________________________________________________
What's New on rajeevnet.com:
o Firewalling HTTP traffic using reverse SQUID proxy.
   http://www.rajeevnet.com/hacks_hints/security/rev-squid-proxy.html
____________________________________________________________________

---------------------------------------------------------------------------
Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off any course! All of our class sizes are guaranteed to be 10 students or less to facilitate one-on-one interaction with one of our expert instructors. Attend a course taught by an expert instructor with years of in-the-field pen testing experience in our state of the art hacking lab. Master the skills of an Ethical Hacker to better assess the security of your organization. Visit us at: http://www.infosecinstitute.com/courses/ethical_hacking_training.html
----------------------------------------------------------------------------


  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]