Chapter 1. Red Hat Network Overview

Have you ever read about a new version of a software package and wanted to install it but could not find it?
Have you ever tried to find an RPM through an Internet search engine or an RPM repository and been linked to an unknown site?
Have you ever tried to find an RPM but instead found only source files that you had to compile yourself?
Have you ever spent hours or even days visiting different websites to see if you have the latest packages installed on your system, only to have to do it again in a few months?
Those days are over with Red Hat Network (RHN). RHN provides the solution to all your system software management needs.
Red Hat Network is an Internet solution for managing a single Red Hat Enterprise Linux system or a network of Red Hat Enterprise Linux systems. All Security Alerts, Bug Fix Alerts, and Enhancement Alerts (collectively known as Errata Alerts) can be downloaded directly from Red Hat or your own custom collection. You can even schedule updates for delivery to your system immediately after release.
The main components of Red Hat Network are as follows:
  • the Red Hat Update Agent
  • the Red Hat Network website, whether this is hosted by the central RHN Servers, an RHN Satellite Server, or fed through an RHN Proxy Server
  • Red Hat Network Daemon
  • the Red Hat Network Registration Client - for systems running Red Hat Enterprise Linux 2.1 only.
The Red Hat Update Agent (up2date) provides your initial connection to Red Hat Network. Red Hat Enterprise Linux 3 and newer systems use the Red Hat Update Agent to register with RHN. Registration involves creating a unique RHN username and password, probing the hardware on your system to create a Hardware Profile, and probing the software packages installed on your system to create a Package Profile. This information is sent to RHN and RHN returns a unique System ID to your system. Once registered, the Red Hat Update Agent enables channel subscription, package installs, and management of System Profiles. See Chapter 2, Red Hat Update Agent for further information.
The Red Hat Update Agent, as the base component of RHN, is designed to manage a single system. It allows the system's superuser to view and apply Errata to the system. The RHN web interface facilitates the management, monitoring, and provisioning of a large deployment of systems, including the configuration of the Red Hat Update Agent for each system.
The Red Hat Network Daemon (rhnsd) runs in the background as a service and probes the Red Hat Network for notifications and updates at set time intervals (see Chapter 3, Red Hat Network Daemon for further information). This daemon is necessary in order to schedule updates or other actions through the website.
The Red Hat Network Registration Client allows you to register your Red Hat Enterprise Linux 2.1 systems with RHN. (Newer versions of Red Hat Enterprise Linux have registration functionality built into the Red Hat Update Agent.) See Chapter 5, Red Hat Network Registration Client for more information.
Many Red Hat Network terms are used throughout this manual. As you read the Red Hat Network Reference Guide, refer to the Glossary as necessary for an explanation of common terms.


For a comparison chart of RHN service levels, refer to

1.1. Update

The RHN Update service is ideal for a user with one Red Hat Enterprise Linux system or a small number of Red Hat Enterprise Linux systems. Updated Subscription to Update can be purchased at
With each Update subscription, you receive the following services:
  • Download Software — For customers who have purchased subscriptions to Red Hat Network, ISO images are available for immediate download.
  • Priority Access during periods of high load — When Red Hat releases a large erratum, users with Priority Access can be guaranteed that they will be able to access the updated packages immediately.
  • RHN Support Access — All paying customers of Red Hat Network receive web based support for their RHN questions.
  • Errata Notification, Multiple Systems — Subscriptions for multiple systems means Errata notification for Errata to all of those systems. Note that only one email is distributed per each Erratum, regardless of the number of systems affected.
  • Errata Updates, Multiple Systems — Get quick updates for multiple systems with an easy button click for each system.