Authentication-method lists

To implement one or more authentication methods for securing access to the device, you configure authentication-method lists that set the order in which the authentication methods are consulted.

In an authentication-method list, you specify the access method (Telnet, SNMP, and so on) and the order in which the device tries one or more of the following authentication methods:

  • Local Telnet login password
  • Local password for the Super User privilege level
  • Local user accounts configured on the device
  • Database on a TACACS or TACACS+ server
  • Database on a RADIUS server
  • No authentication
Note: The TACACS/TACACS+, RADIUS, and Telnet login password authentication methods are not supported for SNMP access.
Note: To authenticate Telnet access to the CLI, you also must enable the authentication by entering the enable telnet authentication command at the global CONFIG level of the CLI. You cannot enable Telnet authentication using the Web Management Interface.
Note: You do not need an authentication-method list to secure access based on ACLs or a list of IP addresses. Refer to ACL usage to restrict remote access or Remote access restrictions.

In an authentication-method list for a particular access method, you can specify up to seven authentication methods. If the first authentication method is successful, the software grants access and stops the authentication process. If the access is rejected by the first authentication method, the software denies access and stops checking.

However, if an error occurs with an authentication method, the software tries the next method on the list, and so on. For example, if the first authentication method is the RADIUS server, but the link to the server is down, the software will try the next authentication method in the list.

Note: If an authentication method is working properly and the password (and user name, if applicable) is not known to that method, this is not an error. The authentication attempt stops, and the user is denied access.

The software will continue this process until either the authentication method is passed or the software reaches the end of the method list. If the Super User level password is not rejected after all the access methods in the list have been tried, access is granted.