A task that is scheduled by a system administrator using Red Hat Network to be performed on one or more client systems. For example, an action can be scheduled to update the kernel packages on all the systems within a selected group.
Activation Key
RHN Management and Provisioningcustomers can generate activation keys through the RHN website. Each unique key can then be used to register a Red Hat system, entitle the system to RHN, subscribe the system to specific channels, and subscribe the system to RHN system groups through the command line utility rhnreg_ks from the rhn_register package.


Base Channel
A base channel is a type of Channel that consists of a list of packages based on a specific architecture and Red Hat release. For example, all the packages in Red Hat Enterprise Linux AS 3 for the x86 architecture make a base channel.
Bug Fix Alert
An Errata Alert that pertains to a bug fix.
Bugzilla is an online application ( that allows users to communicate directly with the developers. From Bugzilla, users can submit bug reports and feature requests for Red Hat Enterprise Linux and related open source packages.


A channel is a list of packages. Channels are used to choose packages to be installed from client systems. Every client system must be subscribed to one Base Channel and can be subscribed to one or more Child Channel .
Child Channel
A child channel is a Channel associated with a Base Channel but contains extra packages.
Client System


Digital Certificate
A client component in XML format that is stored in the /etc/sysconfig/rhn/systemid file on registered systems. Red Hat Network verifies this certificate to authenticate the registered system before each connection. This certificate is issued by Red Hat and passed to the system as part of the registration process. It includes unique information about the registered system to avoid fraudulent use.


Email Notification
Similar to an Errata Alert , except the information is delivered via email. If the email notifications option is selected, notifications are sent for every Red Hat Network Errata Alert . The email includes the type of Errata Alert, summary of the Errata, description of the Errata, and a list of which systems are affected by the report.
Enhancement Alert
An Errata Alert that pertains to a package enhancement request.
Entitled Server
A server that is subscribed to an RHN service level. Because the server is entitled, the RHN website can be used to manage its packages.
Information published by Red Hat describing security fixes, bug fixes, and package enhancements for Red Hat Enterprise Linux. The information includes the topics of the Errata, Bugzilla bug IDs, relevant releases/architectures, solutions including required RPMs, and MD5 checksums for verification. Errata are also available at Each RHN Errata Alert is based on the Red Hat Enterprise Linux Errata List.
Security issues and bug fixes are submitted by Red Hat engineers as well as the Linux community through Bugzilla which generates a bug report for each issue. Red Hat engineering evaluates the reports, resolves the bug, and generates new RPM packages. After the Red Hat quality assurance team tests new packages they are placed on the Red Hat Public File Server and on the Red Hat Network Server and an Errata is generated.
Errata Alert
RHN Errata Alert that updated packages based on Red Hat Errata are available for one or more systems within an organization. There are three types of Errata Alerts: Security Alerts, Bug Fix Alerts, and Enhancement Alerts.


One of the RHN service level offerings. It has more features than the Update service level, including user management, system groups, and enhanced system details.


Notification Method
An email address to which RHN Monitoring messages will be sent.


Organization Administrator
Organization Administrator are sets of users that have the highest level of control over an organization's Red Hat Network account. Members of this group can add users, systems, and system groups to the organization as well as remove them. An Organization Administrator can also give users administrative privileges to system groups. An RHN organization must have at least one member of the Organization Administrator group.


All software in Red Hat Enterprise Linux is divided into software packages. Software updates are released in the form of RPM packages that can be installed on a Red Hat Enterprise Linux system.
A set of criteria that is either a template or a set of values assigned to a system that is used to measure the performance of a system.
Probe State
The measure of a probe's adherence to its defined criteria. States include: OK, Warning, Critical, Pending, Unknown
Probe Suite
collection or group of RHN Monitoring Probes.
One of the RHN service level offerings. It has more features than the Management service level, including kickstarting, reconfiguring, tracking, and reverting systems.


Red Hat Network Daemon
The RHN client daemon (rhnsd) that periodically polls Red Hat Network for scheduled actions.
Registered System
A system that is registered with Red Hat Network. Also known as a client system.
A software package manager that was developed by Red Hat, Inc. It can be used to build, install, query, verify, update, and uninstall software packages. All software updates from RHN are delivered in RPM format.
RPM Database
Each Red Hat Enterprise Linux system has an RPM database that stores information about all the RPM packages installed on the system. This information includes the version of the package, which files were installed with the package, a brief description of the package, the installation date, and more.
RPM Update
Red Hat Network option to deliver the RPM packages based on the Errata Alert list to a client system without user intervention. If this feature is selected, packages are delivered through the Red Hat Network Daemon running on the client system.
Red Hat Network Registration Client
The RHN client application (rhn_register) that collects information about the client system, creates a System Profile and Digital Certificate , establishes a connection with the Red Hat Network servers, and registers the system with Red Hat Network.
Red Hat Update Agent
The RHN client application (up2date) that allows users to retrieve and install all updated packages for the client system on which the application is run. Use the Red Hat Update Agent Configuration Tool to configure its preferences, including whether to install the packages after they are downloaded.


Security Alert
An Errata Alert that pertains to system security.
Service Level
A Red Hat Network subscription service. Different service levels offer different features of RHN. There are three paid service levels currently available: RHN Update, RHN Management, and RHN Provisioning.
System Directory
The System Directory section of Red Hat Network allows an organization to divide its client systems into system groups. Only members of the Organization Administrator group can add systems to the organization.
System ID
A unique string of characters and numbers that identifies a registered system. It is stored in the system's Digital Certificate .
System Profile
Hardware and software information about the client system. It is created during the registration process. The software information is a list of RPM packages and their versions installed on the client system. The System Profile is used to determine every Errata Alert relevant to each client system.
System Set Manager
Interface that allows users to perform actions on multiple systems. Actions include applying Errata Updates, upgrading packages, and adding/removing systems to/from system groups.


One of the RHN service level offerings. Update was formerly called Basic. Update offers the same services as the Basic subscription did, plus more new features.


Virtual Guest
Any of the virtual instances running on the virtual host, under the control of the hypervisor. Also referred to as domain U or domU.
Virtual Host
The physical system that supports the hypervisor and all guest systems. The virtual host may also be referred to as domain 0, or dom0.


Yellowdog Updater Modified (yum)
The Yellowdog Updater Modified is the Red Hat Network client application (yum) that allows users to retrieve and install new or updated packages for the client system on which the application is run.