60 Chapter 4. Red Hat Network WebsiteWarningChanging a system’s entitlement is an irreversible action. You may be unable to change the entitle-ment levels of some systems. For more information, refer to the RHN entitlement policy linked fromthe System Entitlements page.In addition, you may entitle all newly registered systems to the Managements service level at onceby clicking the Auto-Entitle Newest Servers Now link at the bottom of the page. To use this link,which appears only when new, unentitled systems exist, first make sure you have enough Managemententitlements available. If you need to purchase additional entitlements, click the Buy them now linkat the top of the page. After auto-entitling, a message appears at the top of the System Entitlementspage indicating the number of systems successfully entitled to the Management service level.4.4.6. Advanced SearchThe System Search page allows you to search through your systems according to specific criteria.These criteria include custom system information, system details, hardware, devices, interface, net-working, packages, and location. The activity selections (Days Since Last Checkin, for instance) canbe especially useful in finding and removing outdated System Profiles. Type the keyword, select thecriterion to search by, use the radio buttons to identify whether you wish to query all systems or onlythose loaded in the System Set Manager, and click the Search button. Yo may also select the InvertResult checkbox to reverse your results list.The results appear at the bottom of the page. For details about using the resulting system list, refer toSection 4.4.2 Systems.4.4.7. Activation KeysRHN Management and Provisioning customers can generate activation keys through the RHN web-site. These keys can then be used to register the Red Hat Linux system, entitle the system to an RHNservice level and subscribe the system to specific channels and system groups through the commandline utility rhnreg_ks. Refer to Section 2.5 Registering with Activation Keys for instructions on use.NoteSystem-specific activation keys created through the Reactivation subtab of the System Details pagedo not show up in this list because they are not reusable across systems.To generate an activation key:1. Select Systems => Activation Keys from the top and left navigation bars.2. Click the create new key link at the top-left corner.3. Provide the following information:• Description — User-defined description to identify the generated activation key.• Usage Limit — The number of times the key can be used to register a system before theactivation key is disabled. Leave blank for unlimited use.• Base Channel — The primary channel for the key. Selecting nothing will enable you to selectfrom all child channels, although systems can be subscribed to only those that are applicable.