Spam filter gateway using linux
From My Big Bad Wiki
Contents |
Introduction
I have an Exchange 2003 server which has its port 25 NAT'd with my router. The SPAM that I receive has gotten so bad that I've basically stopped using that email address completely and now mostly live in Gmail. Well, I want to start using it again, so it's time to come up with a plan. I don't want to subscribe to some service, install some commercial server tool, or have to maintain some peice of software at the client level. I want this Free, Free, Free. I have some older computers laying around, time to put them back to work.
With this page, I plan document the methods I used to use a computer running Linux and FOSS to filter out SPAM and viruses and continue to deliver good emails to an internal Exchange server.
I plan to follow this guide to get me rolling. In the end, this document may look similar.
Prerequisites
Operating System
- Base Debian 3.2(Etch) install
- Considering moving to Ubuntu for similar instructions but newer packages
Installing and Configring Applications
Postfix
apt-get install postfix
Modify the main.cf file
pico -w /etc/postfix/main.cf
Add
myhostname = serv.domain.net mydomain = domain.net myorgin = $mydomain inet_interfaces = all mydestination = $myhostname, localhost.$mydomain $mydomain mynetwork_style = host relay_domains = domain.net transport_maps = hash:/etc/postfix/transport append_at_myorigin = no
Create a transport file
pico -w /etc/postfix/transport
Add
domain.net smtp:[192.168.16.2]
Run this command
postmap /etc/postfix/transport
Restart Postfix
/etc/init.d/postfix stop /etc/init.d/postfix start
MailScanner
apt-get install mailscanner
pico -w /etc/postfix/main.cf
header_checks = regexp:/etc/postfix/header_checks
pico -w /etc/postfix/header_checks
/^Received:/ HOLD
pico -w /etc/MailScanner/MailScanner.conf
Run As User = postfix ## Uncomment this line #Run As User = Debian-exim ## Comment out this line Run As Group = postfix #Run As Group = Debian-exim Incoming Queue Dir = /var/spool/postfix/hold Outgoing Queue Dir = /var/spool/postfix/incoming MTA = postfix
chown postfix.postfix /var/spool/MailScanner/ chown postfix.postfix /var/spool/MailScanner/incoming chown postfix.postfix /var/spool/MailScanner/quarantine chown postfix.postfix /var/lib/MailScanner/ chown postfix.postfix /var/run/MailScanner/ chown postfix.postfix /var/lock/subsys/MailScanner/
pico -w /etc/default/mailscanner
run_mailscanner=1
ClamAV
apt-get install clamav
TODOS
- Better documentation
- Figure out how to improve SpamAssassin (So many messages that get through are so obviously spam but with an insane low score)
Did this help you?
Please send me a comment letting me know if this helped you at all. I've had folks actually want to donate a few bucks for helping, and I want make it known that this information is provided for free.
