Default (non-software RAID1) CentOS install

Close ALL port forwards in the firewall  to the server IP we are about to install
Install CentOS from DVD by booting from it.  Set system time to UTC.
Partition /dev/sda1 as “boot” 100Meg ext3
Partition /dev/sda2 as “/ “ 74000Meg ext3
Partition /dev/sda3 as “swap” 1900Meg
Set static IP, netmask, gateway, DNS server
Set hostname to something like "asterisk.local".  If you have multiple installs it is important to make this hostname unique for each install so when you get email notifications you will know which PBX is sending it.

Make eth0 and eth1 identical except eth0 is active on boot and eth1 is NOT!  That way if eth0 ever fails you can easily switch over the cable and activate eth1.

Ensure that all package groups and modules in default and custom install packages are DE-selected for install (including "base system") so that only a bare minimal install is done:

For performance and security reasons it is important to update the system immediately after install.
yum -y update

The following packages also need to be installed with yum:

yum groupinstall core
yum groupinstall base

yum install gcc gcc-c++ wget bison mysql-devel mysql-server php php-mysql php-pear php-pear-DB php-mbstring nano ntp tftp-server httpd make ncurses-devel libtermcap-devel sendmail sendmail-cf caching-nameserver sox newt-devel libxml2-devel libtiff-devel php-gd audiofile-devel gtk2-devel

Disable Firewall and SELinux
setup agent

Go to firewall configuration and ensure SELinux and Firewall are disabled

Reboot
reboot