Specifications

Chapter 5: Security
Extreme Networks EAS 100-24t Switch Software Manual
122
● TACACS+ (Terminal Access Controller Access Control System plus) - Provides detailed access
control for authentication for network devices. TACACS+ is facilitated through Authentication
commands via one or more centralized servers. The TACACS+ protocol encrypts all traffic between
the Switch and the TACACS+ daemon, using the TCP protocol to ensure reliable delivery
In order for the TACACS/XTACACS/TACACS+/RADIUS security function to work properly, a
TACACS/XTACACS/TACACS+/RADIUS server must be configured on a device other than the Switch,
called an Authentication Server Host and it must include usernames and passwords for authentication.
When the user is prompted by the Switch to enter usernames and passwords for authentication, the
Switch contacts the TACACS/XTACACS/TACACS+/RADIUS server to verify, and the server will
respond with one of three messages:
● The server verifies the username and password, and the user is granted normal user privileges on
the Switch.
● The server will not accept the username and password and the user is denied access to the Switch.
● The server doesn't respond to the verification query. At this point, the Switch receives the timeout
from the server and then moves to the next method of verification configured in the method list.
The Switch has four built-in Authentication Server Groups, one for each of the TACACS, XTACACS,
TACACS+ and RADIUS protocols. These built-in Authentication Server Groups are used to authenticate
users trying to access the Switch. The users will set Authentication Server Hosts in a preferable order in
the built-in Authentication Server Groups and when a user tries to gain access to the Switch, the Switch
will ask the first Authentication Server Hosts for authentication. If no authentication is made, the
second server host in the list will be queried, and so on. The built-in Authentication Server Groups can
only have hosts that are running the specified protocol. For example, the TACACS Authentication
Server Groups can only have TACACS Authentication Server Hosts.
The administrator for the Switch may set up six different authentication techniques per user-defined
method list (TACACS/XTACACS/TACACS+/RADIUS/local/none) for authentication. These
techniques will be listed in an order preferable, and defined by the user for normal user authentication
on the Switch, and may contain up to eight authentication techniques. When a user attempts to access
the Switch, the Switch will select the first technique listed for authentication. If the first technique goes
through its Authentication Server Hosts and no authentication is returned, the Switch will then go to
the next technique listed in the server group for authentication, until the authentication has been
verified or denied, or the list is exhausted.
Please note that when the user logins to the device successfully through TACACS/XTACACS/
TACACS+/RADIUS server or none method, the “user” priviledge level is the only level assigned. If the
user wants to get the administration privilege level, the user must use the “enable admin” command to
promote his privilege level.
NOTE
TACACS, XTACACS and TACACS+ are separate entities and are not compatible. The Switch and the
server must be configured exactly the same, using the same protocol. (For example, if the Switch is set up for
TACACS authentication, so must be the host server.)
Authentication Policy Settings
This window offers an administrator-defined authentication policy for users trying to access the Switch.
When Enabled, the device will check the Login Method List and choose a technique for user
authentication upon login.