Kickstart is the automated installation method that system administrators use to install Red Hat Enterprise Linux. Using kickstart, a single file is created, containing the answers to all the questions that would normally be asked during a typical installation.

Red Hat Enterprise Linux 5.6 features improved driver support for devices required during the installation process. Support for the following drivers and devices is added to the installer in this release:

Para-virtualized drivers (the virtio drivers) increase the performance for a virtual machine's block and network devices.

Libvirt is a hypervisor-independent virtualization API that is able to interact with the virtualization capabilities of a range of operating systems. libvirt provides a common, generic and stable layer to securely manage virtualized guests on a host.

pvclock enables a guest to read the clock time of the host. In Red Hat Enterprise Linux 5.6, a global synchronization point is added to pvclock, providing a more stable time source for guests.

The virtio-serial driver has been added, enabling vmchannel capabilities on Red Hat Enterprise Linux 5.6 guests operating on Red Hat Enterprise Linux 6 hosts. VMchannel is a transport mechanism used for communication between the host userspace and guest userspace.

The Xen xenoprof command in Red Hat Enterprise Linux 5.6 includes added definitions to recognize Core i7 and Atom processors.

On most modern networks, including the Internet, users locate other computers by name. This frees users from the daunting task of remembering the numerical network address of network resources. The most effective way to configure a network to allow such name-based connections is to set up a Domain Name Service (DNS) or a nameserver, which resolves hostnames on the network to numerical addresses and vice versa.

The kernel features the Netlink Drop Monitor (DROP_MONITOR) service that provides detailed network packet loss monitoring. Red Hat Enterprise Linux 5.6 features the new dropwatch utility to interface with the drop monitor service, and return the results to userspace.

Ethernet bridge tables (ebtables) is a firewalling tool to transparently filter network traffic passing a bridge. The filtering possibilities are limited to link layer filtering and basic filtering on higher network layers. ebtables is a new package for the Red Hat Enterprise Linux 5.6 release.

Hypertext Preprocessor (PHP) is an HTML-embedded scripting language commonly used with the Apache HTTP Web server. Version 5.3.3 of PHP is now available in Red Hat Enterprise Linux 5.6 as the separate php53 package.

mod_nss provides strong cryptography for the Apache Web server via the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols, using the Network Security Services (NSS) security library. In this release, mod_nss has been updated to version 1.0.8, adding support for the Online Certificate Status Protocol (OCSP)

The fourth extended filesystem (ext4) is now a fully supported feature in Red Hat Enterprise Linux 5.6. ext4 is based on the third extended filesystem (ext3) and features a number of improvements, including: support for larger file sizes and offsets, faster and more efficient allocation of disk space, no limit on the number of subdirectories within a directory, faster file system checking, and more robust journaling.

The System Security Services Daemon (SSSD) is a new feature in Red Hat Enterprise Linux 5.6 that implements a set of services for central management of identity and authentication. Centralizing identity and authentication services enables local caching of identities, allowing users to still identify in cases where the connection to the server is interrupted. SSSD supports many types of identity and authentication services, including: Red Hat Directory Server, Active Directory, OpenLDAP, 389 Directory Server, Kerberos and LDAP.

Samba is a suite of programs which use NetBIOS over TCP/IP (NetBT) to enable the sharing of files, printers and other information. This package provides a Server Message Block or SMB server (also known as a Common Internet File System or CIFS server) which can provide network services to SMB/CIFS clients.

IPA Font is a JIS X 0213:2004 compliant Japanese OpenType font provided by Information-Technology Promotion Agency, Japan. Red Hat Enterprise Linux 5.6 introduces the new ipa-gothic-fonts package, containing the Gothic (sans-serif) style font and the new ipa-mincho-fonts package, containing the Mincho-style font.

Red Hat Enterprise Linux 5.6 introduces support for the Wacom Cintiq 21UX2 graphics tablet.

The Ghostscript suite provides a PostScript(TM) interpreter, a set of C procedures (the Ghostscript library, which implements the graphics capabilities in the PostScript language), and an interpreter for PDF files. Ghostscript translates PostScript code into many common, bitmapped formats, like those understood by most printers and displays. This enables users to display PostScript files and print them on non-PostScript printers.

The GNU gettext package provides a set of tools and documentation for producing multi-lingual messages in programs. In Red Hat Enterprise Linux 5.6, gettext has been updated to version 0.17. Note that java and libintl.jar support is discontinued in this updated gettext package.

Subversion (SVN) is a concurrent version control system which enables one or more users to collaborate in developing and maintaining a hierarchy of files and directories while keeping a history of all changes. Subversion in Red Hat Enterprise Linux 5.6 has been updated to version 1.6.11, introducing the new merge tracking and interactive conflict resolution features.

This update provides a new version of the GNU Project Debugger (GDB), featuring the new Python API. This API allows GDB to be automated using scripts written in the Python Programming Language.

The GNU Compiler Collection (GCC) includes, among others, C, C++, and Java GNU compilers and related support libraries. GCC 4.4 is now fully supported in Red Hat Enterprise Linux 5.6, providing interoperability with Red Hat Enterprise Linux 6.

The GNU C Library (glibc) packages contain the standard C libraries used by multiple programs on Red Hat Enterprise Linux. These packages contain the standard C and the standard math libraries. Without these two libraries, the Linux system cannot function properly.

OpenJDK in Red Hat Enterprise Linux 5.6 is updated to IcedTea version 1.7.5. This update provides the following notable additions: