All users configured on the ASA are assigned a privilege level. This privilege level is specified when configuring the username as follows:
hostname(config)# username name password password privilege priv_level
The privilege level can be any value from 0 (least permissive) to 15 (most permissive), with 2 being the default. Do note that if you want to grant the user access to privileged EXEC mode, you should use the range from 2 to 15. For the purpose of assigning read-only access to a user, we will use a privilege level of 5.
AAA refers to authentication, authorization and accounting. It allows us to authenticate who the user is, authorize what that user is allowed to do, and then keep an accounting record showing what that user has done. In order to create a read-only user account, we need to define which commands the user should be granted access to. This requires knowledge of who the user is, so we first need to ensure that user authentication is configured.
To enable AAA authentication, use the following command: