Postfix & Spamassassin integration allowing for custom processing

This assumes that you have postfix installed and running as your SMTP server

First, make sure that you’re root


I probably shouldn’t have to explain that if you’re reading this but just in case; if that last command returned something else than ‘root’ issue the following command

sudo su

and enter your password

step 1: Let’s install the packages we’re gonna need

apt-get update
apt-get install spamassassin spamc

step 2: Now we configure spamassasin

cat /etc/default/spamassassin | sed -e 's#ENABLED=0#ENABLED=1#g' > /etc/default/spamassassin
cat /etc/default/spamassassin | sed -e 's#CRON=0#CRON=1#g' > /etc/default/spamassassin
cat /etc/spamassassin/ | set -e 's## rewrite_header Subject *****SPAM*****#rewrite_header Subject [*****SPAM*****] > /etc/spamassassin/

and we start/restart it

/etc/init.d/spamassassin restart

step 3: We create a little script that will take desired action upon spamassassin flagging

create a user called spamassassin (or whatever you want as long as you keep it consistent)

useradd -m spamassassin

then edit the script file /home/spamassassin/spamcheck and throw the following in it

 # variables
SENDMAIL="/usr/sbin/sendmail -i"
# exit codes from <sysexits.h>
# clean up when done or when aborting.
trap "rm -f /tmp/out.$$" 0 1 2 3 15
# pipe message to spamc
cat | /usr/bin/spamc -u spamd > /tmp/out.$$
# are there more than $SPAMLIMIT stars in X-Spam-Level header? :
if $EGREP -q "^X-Spam-Level: *{$SPAMLIMIT,}" < /tmp/out.$$
# option 1: move spam messages to sideline dir so a human can look at them later:
mv /tmp/out.$$ /home/spamassassin/`date +%Y-%m-%d_%R`-$$
# option 2: divert spam message to an alternate e-mail address:
#$SENDMAIL xyz@xxxx.xx < /tmp/out.$$
# option 3: just delete the spam message
# rm -f /tmp/out.$$
# option 4: still relay the email to the recipient with the subject of the email now containing [*****SPAM*****]
# $SENDMAIL "$@" < /tmp/out.$$
$SENDMAIL "$@" < /tmp/out.$$
# Postfix returns the exit status of the Postfix sendmail command.
exit $?

make sure that you

chown spamassassin:spamassassin /home/spamassassin/spamcheck
chmod 750 /home/spamassassin/spamcheck

step 4: Ok, so we got spamassassin going and a little script that will take an email and throw it in /home/spamassassin if it’s spam (if you chose option1) now we just need to tell postfix to pass all messages to that script

edit /etc/postfix/ and replace

smtp      inet  n       -       -       -       -       smtpd


smtp      inet  n       -       n       -       -       smtpd -o content_filter=spamcheck:dummy

also add the following 2 lines at the bottom of the file (the indentation is important)

spamcheck   unix  -       n       n       -       10      pipe

flags=Rq user=spamassassin argv=/bin/spamcheck -f ${sender} -- ${recipient}

We’re almost there, just restart postfix and you’re good to go!

/etc/init.d/postfix restart

If you wanna test that out, watch the log while you send emails to your servers

tail -f /var/log/syslog

send a clean mail, make sure that it reaches destination, then send something you know will get flagged as spam and make sure it ends up in /home/spamassasin instead of the intended recipient.

The reason we choose option 1 here is because there’s no point in still relaying a flagged email as it will still clog the recipient’s mailbox. On the other hand we don’t want to just delete it if spamassassin makes a mistake we want to play it safe and keep every emails should something arise, we quarantine the bad ones in /home/spamassassin

Lastly, as long as you have postfix just feeding the emails to a script like we just did, it’s easy to become fancier and do all kinds of processing to the email, on my server I actually call a php script that throws emails in a DB.

Silly Apache warning

If the following happens to you:

apache2: Could not reliably determine the server's fully qualified domain name, using for ServerName

just issue a:

echo Servername `cat /etc/hostname` >> /etc/apache2/apache2.conf

Tested on: Ubuntu server 9.04 32b / Ubuntu 12.04 64b


Sad balloons are sad


Proud balloon reporting for duty!


A month after being saved from the corporate world, this is what’s left of the welcome balloons that were kindly positioned at my new desk.

This little guy’s been floating for 38 days. When it finally gives in I’m giving it a Viking funeral.