For IT environments which require legacy Satellite or RHN Classic features, configuration can be done using the RHN Classic content services. The differences are explained in more detail in Section 34.2.1, “Content delivery and subscriptions”; as a summary, RHN Classic is the only content delivery network which works with Red Hat Enterprise Linux 4, Red Hat Enterprise Linux 5.6 and earlier, Red Hat Enterprise Linux 6.0, and Satellite 5 environments. It also offers systems management (such as configuration management) tools not available in Certificate-based Red Hat Network. However, RHN Classic does not provide subscription management tools and is not tightly integrated with the Customer Portal. We strongly encourage you to use Certificate-based Red Hat Network. RHN Classic is provided for legacy systems.