====== Installing Spamassassin on Ubuntu 14.04 Server ======
Spamassassin is a free and open-source mail filter that is used to identify spam using a wide range of tests on mail headers and body. It's very easy to use Spamassassin to protect your mailbox from spammers. The best thing is that we can create rules by ourselves and manage it. Here is how you can install it on your Ubuntu 14.04 server

Before installing Spamassassin, make sure you already have a MTA such as Postfix (or Axigen) installed on your server.

Install Spamassassin
<code>
apt-get install spamassassin spamc
</code>
To run Spamassassin you need to create a new group and user with the home directory /var/log/spamassassin, create the users home directory and change the ownership to the new user:
<code>
groupadd spamd
useradd -g spamd -s /bin/false -d /var/log/spamassassin spamd
mkdir /var/log/spamassassin
chown spamd:spamd /var/log/spamassassin
</code>
Setting Up Spamassassin

Open the spamassassin config file (/etc/default/spamassassin)
To enable Spamassassin find the line
<code>
ENABLED=0
</code>
and change it to
<code>
ENABLED=1
</code>
To enable automatic rule updates in order to get the latest spam filtering rules find the line
<code>
CRON=0
</code>
and change it to
<code>
CRON=1
</code>
Add a variable named SAHOME with the Spamassassin home directory:
<code>
SAHOME="/var/log/spamassassin/"
</code>
Find and change the OPTIONS variable to
<code>
OPTIONS="--create-prefs --max-children 2 --username spamd -H ${SAHOME} -s ${SAHOME}spamd.log"
</code>
This specifies the username Spamassassin will run under, as well as add the home directory, create the log file, and limit the child processes that Spamassassin can run. If you have a high traffic server, you can increase the max-children value.

Start the Spamassassin daemon by using the following code:
<code>
service spamassassin start
</code>