RedHat Enterprise Linux is a LinuxDistribution designed for corporate scenarios, with a medium paced release cycle, a committment to stability, and support to the Nth degree. If someone has certified their software for Linux, it's probably going to be on this. RHEL products are delivered through an annual subscription which includes one year of support services and access to the RedHat Enterprise Network. There are three RHEL flavours:

  • AS (Advanced Server) for 4+ CPUs and clustering
  • ES (Enterprise Server) for 1-2 CPU servers (this is probably the one you want for most cases)
  • WS (Workstation)

Is not available freely from RedHat, but it is Free. If you get the CDs from someone with a subscription, and build the SRPMs yourself, you're allowed to have it. Of course, such a homebuilt RHEL would come without any entitlement for support and services, and so it is pointless.


12-18 month release cycle and five years of support for every version.
With multiple kernel performance enhancements and the audited industry-standard benchmark results to prove it.
RedHat Enterprise Network is included. Provides industry-leading patch/security management and delivery, and optional system monitoring.
Rapid adoption of the RedHatEnterpriseLinux family by ISVs means the applications you need to run your business, from vendors such as Oracle, VERITAS, BEA, CA, and IBM, are available and fully certified. Even better, because all RedHatEnterpriseLinux family members are based on the same core OperatingSystem foundation, when an application is certified on one family member it is automatically certified on them all.
Certified hardware
Major hardware OEMs, including Dell, HP, and IBM, have certified their systems to run with RedHatEnterpriseLinux products.

RHEL 4 was released on 15 February 2005.

An in-depth discussion of what you can and cannot do with Red Hat Enterprise Linux lead to a number of "free reimplementations" of the 100% OpenSource RHEL; see RedHatRebuilds.