With the upgradation to cpwebhosting servers to the hsphere 3.0, now there is a great Support for RedHat EL 4 x86_64 and Centos 4 x86_64. With this it gives a scalability and expanded hardware support.
CentOS-4 is based on Enterprise Linux 4.
Red Hat Enterprise Linux 4 includes the SELinux subsystem, which has been integrated with a dozen outward-facing services, including BIND, NTP, and Apache. This allows for policy-based mandatory access controls, which allows a finer control over user privileges.