
9-8
Using Passwords and TACACS+ To Protect Against Una uthorized Access
TACACS+ Authentication for Central Control of Switch Access Security
Using Passwords and 
TACACS+
TACACS+ Authentication for Central Control of Switch Access SecurityTACACS+ Features
TACACS+ authentication enables you to use a  central server to allow or deny 
access to the Switch 4108GL (and other TACACS-aware devices) in your 
network. This means that you can use a central database to create multiple 
unique username/password sets with associated privilege levels for use by  
individuals who have reason to access the switch from either the switch’s 
console port (local access) or Telnet (remote access).  
Figure 9-4.   Example of TACACS+ Operation
Feature Default Menu CLI Web
view the switch’s authentication configuration n/a     —page 14     —
view the switch’s TACACS+ server contact 
configuration
n/a     —page 15     —
configure the switch’s authentication methods disabled     —page 16     —
configure the switch to contact TACACS+ server(s) disabled     —page 19     —
   B
Switch 4108GL 
Configured for 
TACACS+ Operation
Terminal "A" Directly 
Accessing the Switch 
Via Switch’s Console 
Port
Terminal  "B" Remotely Accessing The Switch Via Telnet
   A
Primary 
TACACS+ 
Server
The switch passes the login 
requests from terminals A and B 
to the TACACS+ server for 
authentication.  The TACACS+ 
server determines whether to 
allow access to the switch and 
what privilege level to allow for 
a given access request.
Access Request                                                                  A1 - A4 :  Path  for Request from       
                                                                                                        Termina l A (Thr ough Co nsole Port) 
TACACS Server                                                               B1 - B4: Path for Request from      
Response                                                                              Terminal B (Through Telnet)     
B1
A2 or 
B2
A3 or 
B3
B4
A1
A4