54 Chapter 4. Red Hat Network WebsiteAfter creating the unique key, it appears in the list of activation keys along with the number of timesit has been used.To change information about a key, such as the channels or groups, click its description in the key list,make your modifications, and click the Update Key button. To remove a key entirely, click the deletekey button in the top-right corner of the edit page.If you do not want a key to be used to activate a system, you can disable it by unselecting the corre-sponding checkbox under the Enabled column in the key list. The key can be re-enabled by selectingthe checkbox. After making these changes, click the Update Keys button on the bottom right-handcorner of the page.To use an activation key, as root from a shell prompt on the system to be registered, run the rhnreg_kscommand. For example:rhnreg_ks --serialnumber=7202f3b7d218cf59b764f9f6e9fa281bThis command performs all the actions that the Red Hat Network Registration Client does. Do notrun the Red Hat Network Registration Client program after running rhnreg_ks.A System Profile, including software and hardware information, is created for the system and sent tothe RHN Servers along with the unique activation key. The system is registered with RHN under theaccount used to generate the key, entitled to the RHN Enterprise service offering, and subscribed to theRHN channels and system groups selected during key generation. The system will not be subscribed tochannels that contain packages not suitable for the system. For example, a Red Hat Linux 7.2 systemcannot be subscribed to the Red Hat Linux 7.1 channel.The unique Digital Certificate for the system is generated on the system in/etc/sysconfig/rhn/systemid.When using activation keys to assign channels, a couple of rules should be kept in mind:• A key may specify either zero or one base channel. If specified, it must be a custom base channel. Ifnot, the base channel corresponding to the system’s RHL distribution will be chosen. For instance,you may not take a 7.1 system and subscribe it to the 7.2 channel.• A key may specify any number of child channels. For each child channel, subscription is attempted.If the child channel matches the system’s base channel, subscription succeeds. If it does not, thesubscription fails silently. Refer to Section 4.6 for more information.4.5. ErrataIf you click the Errata tab on the top navigation bar, the Errata category and links appear. The pagesin the Errata category allow you to track and manage Errata Updates.TipIf you want to receive an email when Errata Alerts are issued for your system, go to Your RHN =>Your Preferences and select Receive Errata email notifications.Red Hat releases Errata Alerts in three categories, or types: Security Alerts, Bug Fix Alerts, andEnhancement Alerts. Each Errata Alert is comprised of a summary of the problem and the solution,including the RPM packages required to fix the problem.Icons are used to identify the three types of Errata Alerts: