One complaint commonly raised against RHEL is that it lags far behind the state-of-the-art in terms of Linux software. Conservative, well-tested releases are a requirement of a true enterprise Linux distribution, both so that no inconsistencies or problems are introduced into corporate infrastructure and to facilitate the longer product support provided for enterprise editions. At the same time, enterprise distributions need to provide a mechanism for keeping up with fundamental improvements in system software. Some of the versions of software provided with RHEL 3.0, such as OpenLDAP, were old enough that they did not support new and up-to-date features that system administrators need to use this in enterprise deployments. RHEL 4.0 corrects most of these sorts of problems, including a move to the more scalable and powerful 2.6 Linux kernel, but the underlying update/upgrade problem still needs to be addressed beyond vulnerability and bug fixes, which Red Hat seems to do a good job of keeping up with.

The following table shows the versions of some of the most popular GNU/Linux software packages found in Red Hat Enterprise Linux 4.0. For those perhaps new to Linux, this table lists the versions of commonly-used applications and system services such the Common Unix Print Server (CUPS) Evolution mail client, the GCC and GDB packages for compilation and debugging, the GNOME desktop system and the underlying X Window System, the Perl, Python, and Ruby scripting languages, authentication and security packages such as OpenLDAP and OpenSSL, the Open Office desktop office software package, the Linux kernel itself.

Package	RHEL 4.0 Version
CUPS	1.1.22
Evolution	2.0.2
Firefox	1.0
GCC	3.4.3
GDB	6.1
GNOME	2.8.0
KDE	3.3.1
Kernel	2.6.9
OpenOffice	1.1.2
OpenLDAP	2.2.13
OpenSSL	0.9.7a
Perl	5.8.5
Python	2.3.14
Ruby	1.8.1
X11(X.org)	6.8.1

Figure 3 shows the default GNOME 2.8 desktop provided by Red Hat Enterprise Linux 4.

From the Web server point of view, RHEL4 provides httpd (Apache) version 2.0.52, with version 4.3.9 of the PHP scripting language and version 2.01 of the cool webalizer software for analyzing web logs and displaying traffic statistics. I didn't try any of the well-known exploits against PHP 4.3.9, but I suspect that an update will be coming soon for that particular package if Red Hat hasn't already patched them into their version. You should do some testing of this before some random Root Crew shows up and gives your brand new site an unwanted face lift.

From the file server point of view, RHEL 4 supports NFS V4, version 4.1 of the autmounter, and version 1.0.6 of the NFS support utilities. It provides Samba version 3.0.10 and supports version 2.00 of the updated Logical Volume Manager LVM2. I was somewhat disappointed with the fact that RHEL 4.0 does not include the utilities for managing the JFS, ReiserFS, or XFS journaling filesystems on local storage. Apparently, Red Hat believes that EXT3 is the only journaling filesystem suitable for managing local storage in the Enterprise. This is clearly untrue, but RHEL doesn't seem to provide any alternatives if you still want to get product support.

Open Source database fans should be happy that RHEL 4.0 provides MySQL 4.1.7 and Postgresql 7.4.6, along with modern versions of the ODBC connectors for each. RHEL 4.0 is also replete with a rich assortment of mail servers, providing Cyrus IMAPD 2.2.10, exim 4.43, Postfix 2.1.5, and Sendmail 8.13. Associated software includes version 3.0.1 of spamassassin for anyone who is deploying any of these mail servers, and includes version 2.1.5 of mailman for creating and managing mailing lists.

As a side note, if you do a custom install of RHEL4 and install everything, it installs a ton of games, which is somewhat surprising in the enterprise Linux Application Server market. However, if your 32-GB 8-CPU application server is under-utilized, you can always play a mean game of battleship (Kbattleship) on the console while configuring services and run-levels, as shows in Figure 4.

Next: RHEL4 and 2.6 Kernel Notes for Sysadmins »