Configuring the switch for RADIUS authentication

Configure RADIUS authentication for controlling access through one or more of the following:

Serial port
Telnet
SSH
Port-Access (802.1X)
WebAgent

RADIUS authentication on the switch must be enabled to override the default authentication operation which is to automatically assign an authenticated client to the operator privilege level. This applies the privilege level specified by the service type value received from the RADIUS server, see Configuring authentication for the access methods that RADIUS protects.
Configure the switch for accessing one or more RADIUS servers (one primary server and up to two backup servers):
- Server IP address
- (Optional) UDP destination port for authentication requests (default: 1812; recommended)
- (Optional) UDP destination port for accounting requests (default: 1813; recommended)
- (Optional) Encryption key for use during authentication sessions with a RADIUS server. This key overrides the global encryption key you can also configure on the switch, and must match the encryption key used on the specified RADIUS server. (default: null)
NOTE: Step 2 assumes you have already configured the RADIUS servers to support the switch. See your RADIUS server documentation for details.
Configure the global RADIUS parameters.
- Server key: This key must match the encryption key used on the RADIUS servers the switch contacts for authentication and accounting services unless you configure one or more per-server keys.(default: null)
- Timeout period: The timeout period the switch waits for a RADIUS server to reply. (default: 5 seconds; range: 1 to 15 seconds)
- Retransmit attempts: The number of retries when there is no server response to a RADIUS authentication request. (default: 3; range of 1 to 5)
- Server dead-time: The period during which the switch will not send new authentication requests to a RADIUS server that has failed to respond to a previous request. This avoids a wait for a request to time out on a server that is unavailable. If you want to use this feature, select a dead-time period of 1 to 1440 minutes. (default: disabled; range: 1-1440 minutes.) If your first-choice server was initially unavailable, but then becomes available before the dead-time expires, you can nullify the dead-time by resetting it to zero and then trying to log on again. As an alternative, you can reboot the switch, (thus resetting the dead-time counter to assume the server is available) and then try to log on again.
- Number of login attempts: This is actually an aaa authentication command. It controls how many times per session a RADIUS client (and clients using other forms of access) can try to log in with the correct username and password. (default: Three times per session)

For RADIUS accounting features, see Accounting services.

Configuring authentication for the access methods that RADIUS protects

Configure the switch for RADIUS authentication through the following access methods:

Console: Either direct serial-port connection or modem connection.
Telnet: Inbound Telnet must be enabled (the default).
SSH: To use RADIUS for SSH access, first configure the switch for SSH operation.
WebAgent: You can enable RADIUS authentication for WebAgent access to the switch.

You can configure RADIUS as the primary password authentication method for the above access methods. You also need to select either local, none, or authorized as a secondary, or backup, method. Note that for console access, if you configure radius (or tacacs) for primary authentication, you must configure local for the secondary method. This prevents the possibility of being completely locked out of the switch in the event that all primary access methods fail.

Syntax:

aaa authentication <console|telnet|ssh|web|<enable|login <local|radius>> web-based|mac-based <chap-radius|peap-radius>>

Configures RADIUS as the primary password authentication method for console, Telnet, SSH, and/or the WebAgent.

The default primary <enable|login> authentication is local.

<console|telnet|ssh|web>

[<local|none|authorized>]

Provides options for secondary authentication. For console access, secondary authentication must be local if primary access is not local. This prevents you from being locked out of the switch in the event of a failure in other access methods.

<<web-based|mac-based> login> <chap-radius|peap-mschapv2>

Password authentication for web-based or MAC-based port access to the switch. Use peap-mschapv2 when you want password verification without requiring access to a plain text password; it is more secure.

Default: chap-radius

[none|authorized]

Provides options for secondary authentication. The none option specifies that a backup authentication method is not used. The authorized option allows access without authentication.

Default: none.

In certain situations, RADIUS servers can become isolated from the network. Users are not able to access the network resources configured with RADIUS access protection and are rejected. To address this situation, configuring the authorized secondary authentication method allows users unconditional access to the network when the primary authentication method fails because the RADIUS servers are unreachable.


	CAUTION: Configuring `authorized` as the secondary authentication method used when there is a failure accessing the RADIUS servers allows clients to access the network unconditionally. Use this method with care.

Example of AAA authentication using authorized for the secondary authentication method shows an example of the show authentication command displaying authorized as the secondary authentication method for port-access, web-based authentication access, and MAC authentication access. Since the configuration of authorized means no authentication will be performed and the client has unconditional access to the network, the "Enable Primary" and "Enable Secondary" fields are not applicable (N/A).

Example of AAA authentication using authorized for the secondary authentication method

Suppose you already configured local passwords on the switch, but want RADIUS to protect primary Telnet and SSH access without allowing a secondary Telnet or SSH access option (the switch local passwords):

Example configuration for RADIUS authentication


	NOTE: If you configure the Login Primary method as `local` instead of `radius` (and local passwords are configured on the switch), then clients connected to your network can gain access to either the operator or manager level without encountering the RADIUS authentication specified for Enable Primary. See Local authentication process (RADIUS).

Enabling manager access privilege (optional)

In the default RADIUS operation, the switch automatically admits any authenticated client to the login (operator) privilege level, even if the RADIUS server specifies enable (manager) access for that client. Thus, an authenticated user authorized for the manager privilege level must authenticate again to change privilege levels. Using the optional login privilege-mode command overrides this default behavior for clients with enable access. That is, with privilege-mode enabled, the switch immediately allows enable (manager) access to a client for whom the RADIUS server specifies this access level.

Syntax:

[no] aaa authentication login privilege-mode

When enabled, the switch reads the Service-Type field in the client authentication received from a RADIUS server. The following table describes the applicableService-Type values and corresponding client access levels the switch allows upon authentication by the server.

Service-type value

Service-type Value Client access level

Administrative-user
6 manager

NAS-prompt-user 7 operator

Any other type
Any value except 6 or 7 Access Denied

Service-type	Value	Client access level
Administrative-user	6	manager
NAS-prompt-user	7	operator
Any other type	Any value except 6 or 7	Access Denied

This feature applies to console (serial port), Telnet, SSH, and WebAgent access to the switch. It does not apply to 802.1X port-access.

NOTE: While this option is enabled, a Service-Type value other than 6 or 7, or an unconfigured (null) Service-Type causes the switch to deny access to the requesting client.

The no form of the command returns the switch to the default RADIUS authentication operation. The default behavior for most interfaces is that a client authorized by the RADIUS server for Enable (manager) access will be prompted twice, once for Login (operator) access and once for Enable access. In the default RADIUS authentication operation, the WebAgent requires only one successful authentication request. For more information on configuring the Service Type in your RADIUS application, see the documentation provided with the application.

Configuring the switch to access a RADIUS server

This section describes how to configure the switch to interact with a RADIUS server for both authentication and accounting services.


	NOTE: If you want to configure RADIUS accounting on the switch, see Accounting services.

Syntax:

[no] radius-server host <ip-address>

Adds a server to the RADIUS configuration or (with no) deletes a server from the configuration. You can configure up to three RADIUS server addresses. The switch uses the first server it successfully accesses. (See Changing RADIUS-server access order.)

The switch uses the first server it successfully accesses, see Changing RADIUS-server access order.

[auth-port <port-number>]

Optional. Changes the UDP destination port for authentication requests to the specified RADIUS server (host). If you do not use this option with the radius-server host command, the switch automatically assigns the default authentication port number. The auth-port number must match its server counterpart.

Default: 1812

[acct-port <port-number>]

Optional. Changes the UDP destination port for accounting requests to the specified RADIUS server. If you do not use this option with the radius-server host command, the switch automatically assigns the default accounting port number. The acct-port number must match its server counterpart.

Default: 1813

[dyn-authorization]

Enables or disables dynamic authorization control from this host.

Default: Disabled

[key <key-string>]

Optional. Specifies an encryption key for use during authentication (or accounting) sessions with the specified server. This key must match the encryption key used on the RADIUS server. Use this command only if the specified server requires a different encryption key than configured for the global encryption key.

Use the no form of the command to remove the key for a specified server.

Suppose you have configured the switch as shown in Configuration for RADIUS server before changing the key and adding another server and you now need to make the following changes:

Change the encryption key for the server at 10.33.18.127 to "source0127".
Add a RADIUS server with an IP address of 10.33.18.119 and a server-specific encryption key of "source0119".

Configuration for RADIUS server before changing the key and adding another server

HP Switch# show radius
 Status and Counters - General RADIUS Information
  Deadtime(min) : 0
  Timeout(secs) : 5
  Retransmit Attempts : 5
  Global Encryption Key :
                  Auth  Acct
  Server IP Addr  Port  Port  Encryption Key
  --------------- ----  ----  ---------------------
  10.33.18.127    1812  1813  TempKey01

To make these changes, perform the following:

Configuration for RADIUS server after changing the key and adding another server

HP Switch(config)# radius-server host 10.33.18.127 key source0127 

*
HP Switch(config)# radius-server host 10.33.18.119 key source0119 

**
HP Switch(config)# show radius

 Status and Counters - General RADIUS Information

  Deadtime(min) : 0
  Timeout(secs) : 5
  Retransmit Attempts : 5
  Global Encryption Key :
  
                  Auth  Acct
  Server IP Addr  Port  Port  Encryption Key
  --------------- ----  ----  ----------------
  10.33.18.127    1812  1813  source0127
  10.33.18.119    1812  1813  source0119

* Changes the key for the existing server to “source0127”

** Adds the new RADIUS server with its required “source0119” key.

To change the order in which the switch accesses RADIUS servers, see Changing RADIUS-server access order.

Configuring the switch global RADIUS parameters

Configure the switch for the following global RADIUS parameters:

Number of login attempts: In a given session, this specifies how many tries at entering the correct username and password pair are allowed before access is denied and the session terminated. This is a general aaa authentication parameter and is not specific to RADIUS.
Global server key: The server key the switch uses for contacts with all RADIUS servers for which there is not a server-specific key configured by radius-server host <ip-address> key <key-string>. This key is optional if you configure a server-specific key for each RADIUS server entered in the switch.
Server timeout: Defines the time period in seconds for authentication attempts. If the timeout period expires before a response is received, the attempt fails.
Server dead time: Specifies the time in minutes during which the switch avoids requesting authentication from a server that has not responded to previous requests.
Retransmit attempts: If the first attempt to contact a RADIUS server fails, this specifies how many retries to allow the switch to attempt on that server.
Change of Authorization port: The dyn-autz-port parameter specifies the UDP port number that listens for the Change of Authorization and Disconnect messages.

Syntax:

aaa authentication num-attempts <1-10>

Specifies how many tries for entering the correct username and password are allowed before shutting down the session due to input errors.

Default: 3; Range: 1–10.

[no] radius-server

key <global-key-string>

Specifies the global encryption key the switch uses with servers for which the switch does not have a server-specific key assignment. This key is optional if all RADIUS server addresses configured in the switch include a server-specific encryption key.

Default: Null.

dead-time <1-1440>

Optional. Specifies the time in minutes during which the switch will not attempt to use a RADIUS server that has not responded to an earlier authentication attempt.

Default:0; Range: 1–1440 minute

dyn-autz-port <1024-49151>

Specifies the UDP port number that listens for Change of Authorization or Disconnect messages. The range of ports is 1024–49151.

Default: 3799

radius-server timeout <1-15>

Specifies the maximum time the switch waits for a response to an authentication request before counting the attempt as a failure.

Default: 5 seconds; Range: 1–15 seconds

radius-server retransmit <1-5>

If a RADIUS server fails to respond to an authentication request, specifies how many retries to attempt before closing the session.

Default: 3; Range: 1–5


	NOTE: Where the switch has multiple RADIUS servers configured to support authentication requests, if the first server fails to respond, then the switch tries the next server in the list, and so-on. If none of the servers respond, then the switch attempts to use the secondary authentication method configured for the type of access being attempted (console, Telnet, or SSH). If this occurs, see the “Troubleshooting” chapter of the Management and Configuration Guide for your switch.

Example:

Suppose your switch is configured to use three RADIUS servers for authenticating access through Telnet and SSH. Two of these servers use the same encryption key. In this case the plan is to configure the switch with the following global authentication parameters:

Allow only two tries to correctly enter username and password.
Use the global encryption key to support the two servers that use the same key. (For this example, assume that you did not configure these two servers with a server-specific key.)
Use a dead-time of five minutes for a server that fails to respond to an authentication request.
Allow three seconds for request timeouts.
Allow two retries following a request that did not receive a response.

Global configuration exercise for RADIUS authentication

HP Switch(config)# aaa authentication num-attempts 2
HP Switch(config)# radius-server key My-Global-KEY-1099
HP Switch(config)# radius-server dead-time 5
HP Switch(config)# radius-server timeout 3
HP Switch(config)# radius-server retransmit 2
HP Switch(config)# write mem

Listings of global RADIUS parameters configured in Global configuration exercise for RADIUS authentication


	NOTE: Step 2 assumes you have already configured the RADIUS servers to support the switch. See your RADIUS server documentation for details.


	NOTE: While this option is enabled, a Service-Type value other than 6 or 7, or an unconfigured (null) Service-Type causes the switch to deny access to the requesting client.

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