Configuring the Switch

3-56

3

Configuring Local/Remote Logon Authentication

Use the Authentication Settings menu to restrict management access based on
specified user names and passwords. You can manually configure access rights on
the switch, or you can use a remote access authentication server based on RADIUS
or TACACS+ protocols.
Remote Authentication Dial-in
User Service (RADIUS) and
Terminal Access Controller
Access Control System Plus
(TACACS+) are logon
authentication protocols that
use software running on a
central server to control
access to RADIUS-aware or
TACACS-aware devices on the
network. An authentication
server contains a database of
multiple user name/password pairs with associated privilege levels for each user
that requires management access to the switch.
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.
Command Usage
By default, management access is always checked against the authentication
database stored on the local switch. If a remote authentication server is used, you
must specify the authentication sequence and the corresponding parameters for
the remote authentication protocol. Local and remote logon authentication control
management access via the console port, web browser, or Telnet.
RADIUS and TACACS+ logon authentication assign a specific privilege level for
each user name/password pair. The user name, password, and privilege level
must be configured on the authentication server. The encryption methods used for
the authentication process must also be configured or negotiated between the
authentication server and logon client. This switch can pass authentication
messages between the server and client that have been encrypted using MD5
(Message-Digest 5), TLS (Transport Layer Security), or TTLS (Tunneled Transport
Layer Security).
You can specify up to three authentication methods for any user to indicate the
authentication sequence. For example, if you select (1) RADIUS, (2) TACACS and
(3) Local, the user name and password on the RADIUS server is verified first. If the
RADIUS server is not available, then authentication is attempted using the
TACACS+ server, and finally the local user name and password is checked.
Web
Telnet
RADIUS/
TACACS+
server
console
1. Client attempts management access.
2. Switch contacts authentication server.
3. Authentication server challenges client.
4. Client responds with proper password or key.
5. Authentication server approves access.
6. Switch grants management access.