A
UTHENTICATION
 C
OMMANDS
3-57
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.
• RADIUS and TACACS+ logon authentication can control 
management access via the console port, a Web browser, or 
Telnet. These access options must be configured on the 
authentication server.
• 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 login 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
username (3-30) - for setting local user names and passwords
Console(config)#authentication login radius local
Console(config)#
b_mgmt.book  Page 57  Tuesday, July 8, 2003  5:24 PM