Dell PowerSwitch S4820T 9.50.1 Configuration Guide for the S4820T System - Page 825

command to each role and as a result, it is easier and much more efficient to administer user rights. If a user's role matches one of the allowed user roles for that command, then command authorization is granted. A constrained RBAC model provides for separation of duty and as a result, provides greater security than the hierarchical RBAC model. Essentially, a constrained model puts some limitations around each role's permissions to allow you to partition of tasks. However, some inheritance is possible. Default command permissions are based on CLI mode (such as configure, interface, router), any specific command settings, and the permissions allowed by the privilege and role commands. The role command allows you to change permissions based on the role. You can modify the permissions specific to that command and/or command option. For more information, see Modifying Command Permissions for Roles . NOTE: When you enter a user role, you have already been authenticated and authorized. You do not need to enter an enable password because you will be automatically placed in EXEC Priv mode. For greater security, the ability to view event, audit, and security system log is associated with user roles. For information about these topics, see Audit and Security Logs. Privilege-or-Role Mode versus Role-only Mode By default, the system provides access to commands determined by the user's role or by the user's privilege level. The user's role takes precedence over a user's privilege level. If the system is in "privilege or role" mode, then all existing user IDs can continue to access the switch even if they do not have a user role defined. To change to more secure mode, use role-based AAA authorization. When role-based only AAA authorization is configured, access to commands is determined only by the user's role. For more information, see Configuring Role-based Only AAA Authorization. Configuring Role-based Only AAA Authorization You can configure authorization so that access to commands is determined only by the user's role. If the user has no user role, access to the system is denied as the user will not be able to login successfully. When you enable role-based only AAA authorization using the aaa authorization role-only command in Configuration mode, the Dell Networking OS checks to ensure that you do not lock yourself out and that the user authentication is available for all terminal lines. Pre-requisites Before you enable role-based only AAA authorization: 1. Locally define a system administrator user role. This will give you access to login with full permissions even if network connectivity to remote authentication servers is not available. 2. Configure login authentication on the console. This ensures that all users are properly identified through authentication no matter the access point. If you do not configure login the authentication on the console, the system displays an error when you attempt to enable role-based only AAA authorization. 3. Specify an authentication method list (RADIUS, TACACS+, or Local). Security 825