Technical data

116 ServerIron ADX Administration Guide
53-1002434-01
Configuring TACACS or TACACS+ security
2
Telnet or SSH prompts when TACACS+ server is unavailable
When TACACS+ is the first method in the authentication method list, the device displays the login
prompt received from the TACACS+ server. If a user attempts to login through Telnet or SSH, but
none of the configured TACACS+ servers are available, the following takes place:
• If the next method in the authentication method list is "enable", the login prompt is skipped,
and the user is prompted for the Enable password (that is, the password configured with the
enable super-user-password command).
• If the next method in the authentication method list is "line", the login prompt is skipped, and
the user is prompted for the Line password (that is, the password configured with the enable
telnet password command).
Configuring TACACS+ authorization
ServerIrons support TACACS+ authorization for controlling access to management functions in the
CLI. Two kinds of TACACS+ authorization are supported:
• Exec authorization determines a user’s privilege level when they are authenticated
• Command authorization consults a TACACS+ server to get authorization for commands entered
by the user
Configuring Exec authorization
When TACACS+ exec authorization is performed, the ServerIron consults a TACACS+ server to
determine the privilege level of the authenticated user. To configure TACACS+ exec authorization
on the ServerIron, enter the following command.
ServerIronADX(config)# aaa authorization exec default tacacs+
Syntax: aaa authorization exec default tacacs+ | none
If you specify none, or omit the aaa authorization exec command from the device’s configuration,
no exec authorization is performed.
A user’s privilege level is obtained from the TACACS+ server in the “brocade-privlvl” A-V pair. If the
aaa authorization exec default tacacs command exists in the configuration, the device assigns the
user the privilege level specified by this A-V pair. If the command does not exist in the
configuration, then the value in the “brocade-privlvl” A-V pair is ignored, and the user is granted
Super User access.
NOTE
If the aaa authorization exec default tacacs+ command exists in the configuration, following
successful authentication the device assigns the user the privilege level specified by the
“brocade-privlvl” A-V pair received from the TACACS+ server. If the aaa authorization exec default
tacacs+ command does not exist in the configuration, then the value in the “brocade-privlvl” A-V pair
is ignored, and the user is granted Super User access.
Also note that in order for the aaa authorization exec default tacacs+ command to work, either the
aaa authentication enable default tacacs+ command, or the aaa authentication login
privilege-mode command must also exist in the configuration.