Asterisk is free software that transforms a computer into a communication server. Asterisk lets you build applications like PBX, VoIP gateway, IVR and ACD. FreePBX is an easy to use GUI (graphical user interface) that controls and manages Asterisk, the world's most popular open source telephony engine software. FreePBX has been developed and hardened by thousands of volunteers over tens of thousands man hours. FreePBX has been downloaded over 5,000,000 times and estimates over 500,000 active phone systems. If you don't know about FreePBX, you are probably paying too much for your phone system.

FreePBX and Asterisk are quite popular these days. I also tried to install FreePBX and Asterisk on a CentOS 5.5, when doing this I read a lot of internet articles and came up with this installation guide. Below I have outlined the steps required to get FreePBX 2.8 working with Asterisk 1.8 on CentOS 5.5.

Preparations

Before you begin, you will need to have 5 different passwords. Some you already know, some you have to generate and write them down. I will refer to these passwords as follows:

PASSWORD1 – Your SSH root password (You have this already)
PASSWORD2 – Used for the asterisk database user (Write this one down)
PASSWORD3 – Used for the FreePBX administrator (Write this one down)
PASSWORD4 – Used for Flash Operator Panel (Write this one down)
PASSWORD5 – Used for the Asterisk Recording Interface (Write this one down)

Pre-install requirement

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yum groupinstall "DNS Name Server"
yum groupinstall "Web Server"
yum groupinstall "Mail Server"
yum groupinstall "MySQL Database"
yum groupinstall "Development Tools" 

 Once you are sure that the needed package groups are installed, you will want to install the prerequisites as follows.

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yum install e2fsprogs-devel keyutils-libs-devel krb5-devel libogg libselinux-devel libsepol-devel libxml2-devel libtiff-devel
yum install gmp php-pear php-pear-DB php-gd php-mysql php-pdo kernel-devel ncurses-devel audiofile-devel libogg-devel
yum install openssl-devel mysql-devel zlib-devel perl-DateManip sendmail-cf sox

Also be sure that wget is installed on your system.

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yum install wget

In the next step we will generate the named.conf file.

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echo "options {" >> /var/named/chroot/etc/named.conf
echo " directory \"/var/named\";" >> /var/named/chroot/etc/named.conf
echo " dump-file \"/var/named/data/cache_dump.db\";" >> /var/named/chroot/etc/named.conf
echo " statistics-file \"/var/named/data/named_stats.txt\";" >> /var/named/chroot/etc/named.conf
echo "};" >> /var/named/chroot/etc/named.conf
echo "include \"/etc/rndc.key\";" >> /var/named/chroot/etc/named.conf
cd /var/named/chroot/etc/
chmod 640 named.conf
chgrp named named.conf
ln -s /var/named/chroot/etc/named.conf /etc/named.conf 

We need to turn off SELinux. If you don't turn SELinux off your setup of FreePBX with Asterisk propably won't work. 

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echo "SELINUX=disabled" > /etc/selinux/config

In this next step we are going to configure iptables voor Asterisk and FreePBX. If you wish you can also disable iptables on your server. If you wish to configure iptables, please make sure the file /etc/sysconfig/iptables looks like this:

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*mangle
:PREROUTING ACCEPT [83145:120824770]
:INPUT ACCEPT [83145:120824770]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [46823:2584014]
:POSTROUTING ACCEPT [46823:2584014]
COMMIT
*filter
:INPUT DROP [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1:60]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p tcp -m tcp ! --tcp-flags FIN,SYN,RST,ACK SYN -m state --state NEW -j DROP
-A INPUT -f -j DROP
-A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG FIN,SYN,RST,PSH,ACK,URG -j DROP
-A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j DROP
-A INPUT -i eth0 -p tcp -m tcp --dport 4445 -j ACCEPT
-A INPUT -i eth0 -p tcp -m tcp --dport 22 -m state --state NEW -j ACCEPT
-A INPUT -i eth0 -p tcp -m tcp --dport 80 -m state --state NEW -j ACCEPT
-A INPUT -i eth0 -p tcp -m tcp --dport 5060 -j ACCEPT
-A INPUT -i eth0 -p udp -m udp --dport 5060 -j ACCEPT
-A INPUT -i eth0 -p udp -m udp --dport 10000:20000 -j ACCEPT
-A INPUT -i eth0 -p tcp -m tcp --dport 5061 -j ACCEPT
-A INPUT -i eth0 -p udp -m udp --dport 5061 -j ACCEPT
-A INPUT -i eth0 -p udp -m udp --dport 4569 -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type 8 -m state --state NEW -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-port-unreachable
COMMIT
*nat
:PREROUTING ACCEPT [164:6544]
:POSTROUTING ACCEPT [148:8939]
:OUTPUT ACCEPT [148:8939]
COMMIT

LAME is required for Asterisk’s audio related functions. You will want to download LAME to a source directory, compile and then install it.

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cd /usr/src
wget http://downloads.sourceforge.net/project/lame/lame/3.98.4/lame-3.98.4.tar.gz?ts=1292626574&use_mirror=cdnetworks-us-1
tar zxvf lame-3.98.4.tar.gz
cd lame-3.98.4
./configure

You can optionally remove the source once you have installed LAME.

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cd ..
rm -fr lame-3.98.4
rm lame-3.98.4.tar.gz

We also need to add DAHDI support if you want to set up conferences in FreePBX / Asterisk. Most of you do want this feature I believe, if not, skip this step.

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cd /usr/src/
wget http://downloads.asterisk.org/pub/telephony/dahdi-linux-complete/releases/dahdi-linux-complete-2.4.0+2.4.0.tar.gz
tar zxvf dahdi-linux-complete-2.4.0+2.4.0.tar.gz
cd dahdi-linux-complete-2.4.0+2.4.0
make all
make install
make config
/etc/init.d/dahdi restart
chkconfig dahdi on

Before continuing, ensure that all packages are up to date and then reboot. 

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yum update
reboot

Installing Asterisk 1.8

Get Asterisk 1.8 and extract it to its own source folder. Afterwards we start the installation immediately.

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cd /usr/src
wget http://downloads.asterisk.org/pub/telephony/asterisk/asterisk-1.8-current.tar.gz
tar xvfz asterisk-1.8-current.tar.gz
cd asterisk-1.8.x.x #Replace 1.8.x.x with the correct version
contrib/scripts/get_mp3_source.sh
./configure
make
menuconfig 

The last command will launch the source configuration manager. Make sure you select the following:

- Head into Channel Drivers and make sure chan_dahdi is selected (only needed if you want to use conferences and installed dahdi in the steps before)
- Head into Add-Ons and make sure app_mysql, app_saycountpl, cdr_mysql, format_mp3, res_config_mysql are selected
- Head into Extra Sound Packages and make sure EXTRAS-SOUNDS-EN-GSM is selected

Save your selections and exit. Now compile the source and install.

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make
make install

You can optionally remove the source directory once you have installed Asterisk.

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cd ..
rm -fR asterisk-1.8.x.x #Replace 1.8.x.x with the correct version
rm asterisk-1.8-current.tar.gz

Installing FreePBX 2.8

Get FreePBX 2.8 and extract it to its own source folder.

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cd /usr/src
wget http://mirror.freepbx.org/freepbx-2.8.0.tar.gz
tar xvfz freepbx-2.8.0.tar.gz
cd freepbx-2.8.0

Start MySQL, create the asterisk databases and run the initial SQL setup scripts.

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/etc/init.d/mysqld start
chkconfig mysqld on
mysqladmin create asterisk
mysqladmin create asteriskcdrdb
mysql asterisk < SQL/newinstall.sql
mysql asteriskcdrdb < SQL/cdr_mysql_table.sql

Start the MySQL command line.

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mysql

Define the user and password for each of the databases.

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GRANT ALL PRIVILEGES ON asteriskcdrdb.* TO asteriskuser@localhost IDENTIFIED BY 'PASSWORD2';
GRANT ALL PRIVILEGES ON asterisk.* TO asteriskuser@localhost IDENTIFIED BY 'PASSWORD2';
flush privileges;
\q

Change the MySQL user to root.

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mysqladmin -u root password 'PASSWORD1'

Create the Asterisk user and set folder permissions.

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useradd -c "Asterisk PBX" -d /var/lib/asterisk asterisk
chown -R asterisk:asterisk /var/run/asterisk
chown -R asterisk:asterisk /var/log/asterisk
chown -R asterisk:asterisk /var/lib/php/session/

Update the Apache configuration file.

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vi /etc/httpd/conf/httpd.conf

In this file change the following settings to the values as listed here:

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# Search for the setting User & Group
User asterisk
Group asterisk
 
# Search for the setting AllowOverride
<Directory />
    Options FollowSymLinks
    AllowOverride All
</Directory>
 
# Search for the setting ServerName
ServerName <your ip or hostname>:80

Start the Apache webserver.

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/etc/init.d/httpd start
chkconfig httpd on

Start Asterisk

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./start_asterisk start

Configure FreePBX.

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./install_amp --username=asteriskuser --password=PASSWORD2 

The next series of prompts will give you default values within square brackets which you can accept by hitting enter. If you wish to change a value, simply type it and hit enter after.

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[asteriskuser]

This is the database user you specified earlier.

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[PASSWORD2]

This is the password for the database user.

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[localhost]

Use the default value.

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[admin]

The username for the FreePBX administrator.

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[amp111]

The password for the FreePBX administrator. It is important to change this. (Use PASSWORD3 you prepared earlier.)

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[/var/www/html]

Use the default value.

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[xx.xx.xx.xx]

The public IP that will be used.

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[passw0rd]

The Flash Operator Panel password. It is important to change this. (Use PASSWORD4 you prepared earlier)

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[extensions]

Use the default value.

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[/var/lib/asterisk/bin]

Use the default value.

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[/usr/local/sbin]

Use the default value.

Change the Asterisk Recording Interface password and turn on user authentication for the web interface by editing the amportal.conf file.

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vi /etc/amportal.conf

Change the ARI_ADMIN_PASSWORD entry to update the ARI password.

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ARI_ADMIN_PASSWORD=PASSWORD5

Change the AUTHTYPE entry to database to enable authentication.

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AUTHTYPE=database

Optionally, you can turn off the FOP completely by changing the following settings.

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FOPRUN=false
FOPDISABLE=true

Save and exit.

Add FreePBX to the boot process.

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echo "/usr/local/sbin/amportal start" >> /etc/rc.local

Reset the permissions of the /var/www/html

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chown -R asterisk:asterisk /var/www/html

Finally, reboot the server one last time.

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reboot

Post installation actions

After you succesfully installed FreePBX and Asterisk, you need to do some extra steps.

First open a browser and go to your Asterisk server by enetering the URL http://<your ip or hostname>. When you are there go to "FreePBX Administration". You will receive an pop-up, fill username "admin" and password "admin". Once logged in, in the left menu click on "Administrators". Then click in the right menu on "admin". Now change the admin password to PASSWORD3 (you prepared it earlier).

Then click on the left menu on the option "Module Admin". Now click on "Check for updates online" and install the updates you want and install the new modules if you like (I installed and updated all modules).

If you installed the module "Music on Hold", which you probably did, please change the upload_max_filesize in /etc/php.ini. Standard this setting is set to 2M. Set it to 20M and restart Apache (/etc/init.d/httpd restart).

Other usefull information

1. You may also need to protect your Asterisk from brute force attacks. Click here to read a article about this.
2. Learn howto add SIP extensions with FreePBX.
3. Howto ring more phones at once when calling a extension.
4. Configure Sipdroid for Android.