Command Line Interface

4-82

4

authentication enable

This command defines the authentication method and precedence to use when
changing from Exec command mode to Privileged Exec command mode with the
enable command (see page 4-11). Use the no form to restore the default.
Syntax
authentication enable {[local] [radius] [tacacs]}
no authentication enable
local - Use local password only.
radius - Use RADIUS server password only.
tacacs - Use TACACS server password.
Default Setting
Local
Command Mode
Global Configuration
Command Usage
RADIUS uses UDP while TACACS+ uses TCP. UDP only offers best effort
delivery, while TCP offers a connection-oriented transport. Also, note that
RADIUS encrypts only the password in the access-request packet from the
client to the server, while TACACS+ encrypts the entire body of the packet.
RADIUS and TACACS+ logon authentication assigns a specific privilege level
for each user name and password pair. The user name, password, and
privilege level must be configured on the authentication server.
You can specify three authentication methods in a single command to indicate
the authentication sequence. For example, if you enter “authentication
enable radius tacacs local,” the user name and password on the RADIUS
server is verified first. If the RADIUS server is not available, then
authentication is attempted on the TACACS+ server. If the TACACS+ server
is not available, the local user name and password is checked.
Example
Related Commands
enable password - sets the password for changing command modes (4-78)
Console(config)#authentication enable radius
Console(config)#