CPanel installation tips

Disk layout

We recommend to use logical volumes (LVM)

swap - twice the server's RAM
/ - 40G (not that large if you want to use separate /var and /home)
/boot - 200M
/tmp - 2G
somewhat more for /var/lib/mysql to store more databases
/home - grow to fill the disk

Network

Set IP address: edit /etc/sysconfig/network-scripts/ifcfg-eth?. cPanel installation guide forbids to use NAT.
Set fully qualified domain name (FQDN): edit /etc/sysconfig/network. cPanel allows to  use only 3rd level domain names (cp.example.com).

Base system installation

Install minimal CentOS.
Check for package groups installed (yum grouplist). Remove (yum groupremove) all of:

• FTP Server
• GNOME Desktop Environment
• KDE (K Desktop Environment)
• Mail Server or E-mail Server
• Mono
• Web Server
• X Window System

for minimal installation only "E-mail server" was installed by default.
Install perl (yum install perl), wget (yum install wget)
Disable SELinux: edit /etc/selinux/config, set "SELINUX=disabled"
Disable iptables: chkconfig iptables off, chkconfig ip6tables off

cPanel installation

cd /home
wget -N http://httpupdate.cpanel.net/latest
sh latest

Post-installation configuration

You can enable firewall now: the best choice is to install CSF, so you could manage firewall rules under WHM menus:
wget http://www.configserver.com/free/csf.tgz && tar -xzf csf.tgz && cd csf && sh install.sh
edit /etc/csf/csf.conf, set TESTING="0" and restart csf (csf -r)
or you can enable iptables (chkconfig iptables on, chkconfig ip6tables on) and open custom ports:

• 20 — FTP TCP inbound/outbound
• 21 — FTP TCP, UDP inbound/outbound
• 22 — SSH TCP inbound
• 25 — SMTP TCP inbound/outbound
• 26 — SMTP TCP inbound/outbound
• 37 — rdate TCP outbound
• 43 — whois TCP outbound
• 53 — DNS TCP/UDP inbound/outbound (inbound is only needed if you run your own public DNS server)
• 80 — HTTP TCP inbound/outbound
• 110 — POP3 TCP inbound
• 113 — ident TCP outbound
• 143 — IMAP4 TCP inbound
• 443 — HTTPS TCP inbound
• 465 — SMTP TLS/SSL TCP/UDP inbound/outbound
• 783 — SpamAssassin TCP/UDP inbound
• 873 — rsync TCP/UDP outbound
• 993 — IMAP4 SSL TCP inbound
• 995 — POP3 SSL TCP inbound
• 2077 — WebDAV TCP/UDP inbound/outbound
• 2078 — WebDAV SSL TCP/UDP inbound/outbound
• 2082 — cPanel TCP inbound
• 2083 — cPanel SSL TCP inbound
• 2086 — WHM TCP inbound
• 2087 — WHM SSL TCP inbound
• 2089 — cPanel license TCP outbound
• 2095 — Webmail TCP inbound
• 2096 — Webmail SSL TCP inbound
• 3306 — MySQL TCP (only if you need to connect remotely)
• 6666 — Chat TCP inbound

Configure WHM (https://<ip addr>:2087) and cPanel (https://<ip addr>:2083) accordingly to your needs.

You can find the most up to date installation guide at cPanel official documentation