Table of Contents

1 AAA Configuration· 1-1

Introduction to AAA· 1-1

Introduction to RADIUS· 1-2

Client/Server Model 1-2

Security and Authentication Mechanisms· 1-3

Basic Message Exchange Process of RADIUS· 1-3

RADIUS Packet Format 1-4

Extended RADIUS Attributes· 1-7

Introduction to HWTACACS· 1-7

Differences Between HWTACACS and RADIUS· 1-8

Basic Message Exchange Process of HWTACACS· 1-8

Protocols and Standards· 1-10

AAA Configuration Task List 1-10

AAA Configuration Task List 1-11

RADIUS Configuration Task List 1-11

HWTACACS Configuration Task List 1-12

Configuring AAA· 1-12

Configuration Prerequisites· 1-12

Creating an ISP Domain· 1-12

Configuring ISP Domain Attributes· 1-13

Configuring AAA Authentication Methods for an ISP Domain· 1-14

Configuring AAA Authorization Methods for an ISP Domain· 1-15

Configuring AAA Accounting Methods for an ISP Domain· 1-17

Configuring Local User Attributes· 1-18

Configuring User Group Attributes· 1-20

Tearing down User Connections Forcibly· 1-21

Configuring the Local EAP Authentication Server 1-21

Displaying and Maintaining AAA· 1-22

Configuring RADIUS· 1-22

Creating a RADIUS Scheme· 1-23

Specifying the RADIUS Authentication/Authorization Servers· 1-23

Specifying the RADIUS Accounting Servers and Relevant Parameters· 1-24

Setting the Shared Key for RADIUS Packets· 1-25

Setting the Upper Limit of RADIUS Request Retransmission Attempts· 1-25

Setting the Supported RADIUS Server Type· 1-26

Setting the Status of RADIUS Servers· 1-26

Configuring Attributes Related to Data to Be Sent to the RADIUS Server 1-27

Setting Timers Regarding RADIUS Servers· 1-28

Configuring RADIUS Accounting-On· 1-30

Enabling the Listening Port of the RADIUS Client 1-30

Configuring the RADIUS Offload Feature· 1-30

Displaying and Maintaining RADIUS· 1-31

Configuring HWTACACS· 1-32

Creating a HWTACACS scheme· 1-32

Specifying the HWTACACS Authentication Servers· 1-32

Specifying the HWTACACS Authorization Servers· 1-33

Specifying the HWTACACS Accounting Servers· 1-34

Setting the Shared Key for HWTACACS Packets· 1-35

Configuring Attributes Related to the Data Sent to HWTACACS Server 1-35

Setting Timers Regarding HWTACACS Servers· 1-36

Displaying and Maintaining HWTACACS· 1-36

AAA Configuration Examples· 1-37

AAA for Telnet Users by a HWTACACS Server 1-37

AAA for Telnet Users by Separate Servers· 1-38

AAA for SSH Users by a RADIUS Server 1-40

Troubleshooting AAA· 1-42

Troubleshooting RADIUS· 1-42

Troubleshooting HWTACACS· 1-44

 

When configuring AAA, go to these sections for information you are interested in:

l          Introduction to AAA

l          Introduction to RADIUS

l          Introduction to HWTACACS

l          Protocols and Standards

l          AAA Configuration Task List

l          Configuring AAA

l          Configuring RADIUS

l          Configuring HWTACACS

l          AAA Configuration Examples

l          Troubleshooting AAA

Introduction to AAA

Authentication, Authorization, and Accounting (AAA) provides a uniform framework for configuring these three security functions to implement network security management.

AAA usually uses a client/server model, where the client runs on the network access server (NAS) and the server maintains user information centrally. In an AAA network, a NAS is a server for users but a client for the AAA servers, as shown in Figure 1-1.

Figure 1-1 AAA networking diagram

 

When a user tries to establish a connection to the NAS and to obtain the rights to access other networks or some network resources, the NAS authenticates the user or the corresponding connection. The NAS can transparently pass the user’s AAA information to the server (RADIUS server or HWTACACS server). The RADIUS/HWTACACS protocol defines how a NAS and a server exchange user information between them.

In the AAA network shown in Figure 1-1, there is a RADIUS server and a HWTACACS server. You can determine the authentication, authorization and accounting methods according to the actual requirements. For example, you can use the HWTACACS server for authentication and authorization, and the RADIUS server for accounting.

The three security functions are described as follows:

l          Authentication: Identifies remote users and judges whether a user is legal.

l          Authorization: Grants different users different rights. For example, a user logging into the server can be granted the permission to access and print the files in the server.

l          Accounting: Records all network service usage information of users, including the service type, start and end time, and traffic. In this way, accounting can be used for not only charging, but also network security surveillance.

You can use AAA to provide only one or two security functions, if desired. For example, if your company only wants employees to be authenticated before they access specific resources, you only need to configure an authentication server. If network usage information is expected to be recorded, you also need to configure an accounting server.

As described above, AAA provides a uniform framework to implement network security management. It is a security mechanism that enables authenticated and authorized entities to access specific resources and records operations of the entities. As the AAA framework thus allows for excellent scalability and centralized user information management, it has gained wide application.

AAA can be implemented through multiple protocols. Currently, the device supports using RADIUS, and HWTACACS for AAA, and RADIUS is often used in practice.

Introduction to RADIUS

Remote Authentication Dial-In User Service (RADIUS) is a distributed information interaction protocol in a client/server model. RADIUS can protect networks against unauthorized access and is often used in network environments where both high security and remote user access are required. Based on UDP, RADIUS uses UDP port 1812 for authentication and 1813 for accounting. RADIUS defines the RADIUS packet format and message transfer mechanism.

RADIUS was originally designed for dial-in user access. With the diversification of access methods, RADIUS has been extended to support more access methods, for example, Ethernet access and ADSL access. It uses authentication and authorization in providing access services and uses accounting to collect and record usage information of network resources.

Client/Server Model

l          Client: The RADIUS client runs on the NASs located throughout the network. It passes user information to designated RADIUS servers and acts on the responses (for example, rejects or accepts user access requests).

l          Server: The RADIUS server runs on the computer or workstation at the network center and maintains information related to user authentication and network service access. It listens to connection requests, authenticates users, and returns the processing results (for example, rejecting or accepting the user access request) to the clients.

In general, the RADIUS server maintains three databases, namely, Users, Clients, and Dictionary, as shown in Figure 1-2:

Figure 1-2 RADIUS server components

 

l          Users: Stores user information such as the usernames, passwords, applied protocols, and IP addresses.

l          Clients: Stores information about RADIUS clients, such as the shared keys and IP addresses.

l          Dictionary: Stores information about the meanings of RADIUS protocol attributes and their values.

Security and Authentication Mechanisms

Information exchanged between a RADIUS client and the RADIUS server is authenticated with a shared key, which is never transmitted over the network. This enhances the information exchange security. In addition, to prevent user passwords from being intercepted in non-secure networks, RADIUS encrypts passwords before transmitting them.

A RADIUS server supports multiple user authentication methods. Moreover, a RADIUS server can act as the client of another AAA server to provide authentication proxy services.

Basic Message Exchange Process of RADIUS

Figure 1-3 illustrates the interaction of the host, the RADIUS client, and the RADIUS server.

Figure 1-3 Basic message exchange process of RADIUS

 

The following is how RADIUS operates:

2)        The host initiates a connection request carrying the username and password to the RADIUS client.

3)        Having received the username and password, the RADIUS client sends an authentication request (Access-Request) to the RADIUS server, with the user password encrypted by using the Message-Digest 5 (MD5) algorithm and the shared key.

4)        The RADIUS server authenticates the username and password. If the authentication succeeds, it sends back an Access-Accept message containing the user’s authorization information. If the authentication fails, it returns an Access-Reject message.

5)        The RADIUS client permits or denies the user according to the returned authentication result. If it permits the user, it sends a start-accounting request (Accounting-Request) to the RADIUS server.

6)        The RADIUS server returns a start-accounting response (Accounting-Response) and starts accounting.

7)        The user accesses the network resources.

8)        The host requests the RADIUS client to tear down the connection and the RADIUS client sends a stop-accounting request (Accounting-Request) to the RADIUS server.

9)        The RADIUS server returns a stop-accounting response (Accounting-Response) and stops accounting for the user.

10)    The user stops access to network resources.

RADIUS Packet Format

RADIUS uses UDP to transmit messages. It ensures the smooth message exchange between the RADIUS server and the client through a series of mechanisms, including the timer management mechanism, retransmission mechanism, and slave server mechanism. Figure 1-4 shows the RADIUS packet format.

Figure 1-4 RADIUS packet format

 

Descriptions of the fields are as follows:

1)        The Code field (1-byte long) is for indicating the type of the RADIUS packet. Table 1-1 gives the possible values and their meanings.

Table 1-1 Main values of the Code field

Code	Packet type	Description
1	Access-Request	From the client to the server. A packet of this type carries user information for the server to authenticate the user. It must contain the User-Name attribute and can optionally contain the attributes of NAS-IP-Address, User-Password, and NAS-Port.
2	Access-Accept	From the server to the client. If all the attribute values carried in the Access-Request are acceptable, that is, the authentication succeeds, the server sends an Access-Accept response.
3	Access-Reject	From the server to the client. If any attribute value carried in the Access-Request is unacceptable, the server rejects the user and sends an Access-Reject response.
4	Accounting-Request	From the client to the server. A packet of this type carries user information for the server to start/stop accounting for the user. It contains the Acct-Status-Type attribute, which indicates whether the server is requested to start the accounting or to end the accounting.
5	Accounting-Response	From the server to the client. The server sends to the client a packet of this type to notify that it has received the Accounting-Request and has correctly started recording the accounting information.

 

2)        The Identifier field (1-byte long) is for matching request packets and response packets and detecting retransmitted request packets. The request and response packets of the same type have the same identifier.

3)        The Length field (2-byte long) indicates the length of the entire packet, including the Code, Identifier, Length, Authenticator, and Attribute fields. The value of the field is in the range 20 to 4096. Bytes beyond the length are considered the padding and are neglected upon reception. If the length of a received packet is less than that indicated by the Length field, the packet is dropped.

4)        The Authenticator field (16-byte long) is used to authenticate replies from the RADIUS server, and is also used in the password hiding algorithm. There are two kinds of authenticators: request authenticator and response authenticator.

5)        The Attribute field, with a variable length, carries the specific authentication, authorization, and accounting information for defining configuration details of the request or response. This field is represented in triplets of Type, Length, and Value.

l          Type: One byte, in the range 1 to 255. It indicates the type of the attribute. Commonly used attributes for RADIUS authentication, authorization and accounting are listed in Table 1-2.

l          Length: One byte for indicating the length of the attribute in bytes, including the Type, Length, and Value fields.

l          Value: Value of the attribute, up to 253 bytes. Its format and content depend on the Type and Length fields.

Table 1-2 RADIUS attributes

No.	Attribute	No.	Attribute
1	User-Name	45	Acct-Authentic
2	User-Password	46	Acct-Session-Time
3	CHAP-Password	47	Acct-Input-Packets
4	NAS-IP-Address	48	Acct-Output-Packets
5	NAS-Port	49	Acct-Terminate-Cause
6	Service-Type	50	Acct-Multi-Session-Id
7	Framed-Protocol	51	Acct-Link-Count
8	Framed-IP-Address	52	Acct-Input-Gigawords
9	Framed-IP-Netmask	53	Acct-Output-Gigawords
10	Framed-Routing	54	(unassigned)
11	Filter-ID	55	Event-Timestamp
12	Framed-MTU	56-59	(unassigned)
13	Framed-Compression	60	CHAP-Challenge
14	Login-IP-Host	61	NAS-Port-Type
15	Login-Service	62	Port-Limit
16	Login-TCP-Port	63	Login-LAT-Port
17	(unassigned)	64	Tunnel-Type
18	Reply_Message	65	Tunnel-Medium-Type
19	Callback-Number	66	Tunnel-Client-Endpoint
20	Callback-ID	67	Tunnel-Server-Endpoint
21	(unassigned)	68	Acct-Tunnel-Connection
22	Framed-Route	69	Tunnel-Password
23	Framed-IPX-Network	70	ARAP-Password
24	State	71	ARAP-Features
25	Class	72	ARAP-Zone-Access
26	Vendor-Specific	73	ARAP-Security
27	Session-Timeout	74	ARAP-Security-Data
28	Idle-Timeout	75	Password-Retry
29	Termination-Action	76	Prompt
30	Called-Station-Id	77	Connect-Info
31	Calling-Station-Id	78	Configuration-Token
32	NAS-Identifier	79	EAP-Message
33	Proxy-State	80	Message-Authenticator
34	Login-LAT-Service	81	Tunnel-Private-Group-id
35	Login-LAT-Node	82	Tunnel-Assignment-id
36	Login-LAT-Group	83	Tunnel-Preference
37	Framed-AppleTalk-Link	84	ARAP-Challenge-Response
38	Framed-AppleTalk-Network	85	Acct-Interim-Interval
39	Framed-AppleTalk-Zone	86	Acct-Tunnel-Packets-Lost
40	Acct-Status-Type	87	NAS-Port-Id
41	Acct-Delay-Time	88	Framed-Pool
42	Acct-Input-Octets	89	(unassigned)
43	Acct-Output-Octets	90	Tunnel-Client-Auth-id
44	Acct-Session-Id	91	Tunnel-Server-Auth-id

 

 

Extended RADIUS Attributes

The RADIUS protocol features excellent extensibility. Attribute 26 (Vender-Specific) defined by RFC 2865 allows a vender to define extended attributes to implement functions that the standard RADIUS protocol does not provide.

A vendor can encapsulate multiple type-length-value (TLV) sub-attributes in RADIUS packets for extension in applications. As shown in Figure 1-5, a sub-attribute that can be encapsulated in Attribute 26 consists of the following four parts:

l          Vendor-ID (four bytes): Indicates the ID of the vendor. Its most significant byte is 0 and the other three bytes contain a code complying with RFC 1700. The vendor ID of H3C is 2011.

l          Vendor-Type: Indicates the type of the sub-attribute.

l          Vendor-Length: Indicates the length of the sub-attribute.

l          Vendor-Data: Indicates the contents of the sub-attribute.

Figure 1-5 Segment of a RADIUS packet containing an extended attribute

 

Introduction to HWTACACS

HW Terminal Access Controller Access Control System (HWTACACS) is an enhanced security protocol based on TACACS (RFC 1492). Similar to RADIUS, it uses a client/server model for information exchange between NAS and HWTACACS server.

HWTACACS is mainly used to provide AAA services for terminal users. In a typical HWTACACS application, a terminal user needs to log into the device for operations, and HWTACACS authenticates, authorizes and keeps accounting for the user. Working as the HWTACACS client, the device sends the username and password to the HWTACACS sever for authentication. After passing authentication and being authorized, the user can log into the device to perform operations.

Differences Between HWTACACS and RADIUS

HWTACACS and RADIUS have many common features, like implementing AAA, using a client/server model, using shared keys for user information security and having good flexibility and extensibility. Meanwhile, they also have differences, as listed in Table 1-3.

Table 1-3 Primary differences between HWTACACS and RADIUS

HWTACACS	RADIUS
Uses TCP, providing more reliable network transmission.	Uses UDP, providing higher transport efficiency.
Encrypts the entire packet except for the HWTACACS header.	Encrypts only the user password field in an authentication packet.
Protocol packets are complicated and authorization is independent of authentication. Authentication and authorization can be deployed on different HWTACACS servers.	Protocol packets are simple and authorization is combined with authentication.
Supports authorized use of configuration commands. For example, an authenticated login user can be authorized to configure the device.	Does not support authorized use of configuration commands.

 

Basic Message Exchange Process of HWTACACS

The following takes a Telnet user as an example to describe how HWTACACS performs user authentication, authorization, and accounting. Figure 1-6 illustrates the basic message exchange process of HWTACACS.

Figure 1-6 Basic message exchange process of HWTACACS for a Telnet user

 

1)        A Telnet user sends an access request to the NAS.

2)        Upon receiving the request, the HWTACACS client sends a start-authentication packet to the HWTACACS server.

3)        The HWTACACS server sends back an authentication response requesting the username.

4)        Upon receiving the response, the HWTACACS client asks the user for the username.

5)        The user inputs the username.

6)        After receiving the username from the user, the HWTACACS client sends to the server a continue-authentication packet carrying the username.

7)        The HWTACACS server sends back an authentication response, requesting the login password.

8)        Upon receipt of the response, the HWTACACS client asks the user for the login password.

9)        The user inputs the password.

10)    After receiving the login password, the HWTACACS client sends to the HWTACACS server a continue-authentication packet carrying the login password.

11)    The HWTACACS server sends back an authentication response indicating that the user has passed authentication.

12)    The HWTACACS client sends the user authorization request packet to the HWTACACS server.

13)    The HWTACACS server sends back the authorization response, indicating that the user is authorized now.

14)    Knowing that the user is now authorized, the HWTACACS client pushes the configuration interface of the NAS to the user.

15)    The HWTACACS client sends a start-accounting request to the HWTACACS server.

16)    The HWTACACS server sends back an accounting response, indicating that it has received the start-accounting request.

17)    The user logs off.

18)    The HWTACACS client sends a stop-accounting request to the HWTACACS server.

19)    The HWTACACS server sends back a stop-accounting response, indicating that the stop-accounting request has been received.

Protocols and Standards

The protocols and standards related to AAA, RADIUS, and HWTACACS include:

l          RFC 2865: Remote Authentication Dial In User Service (RADIUS)

l          RFC 2866: RADIUS Accounting

l          RFC 2867: RADIUS Accounting Modifications for Tunnel Protocol Support

l          RFC 2868: RADIUS Attributes for Tunnel Protocol Support

l          RFC 2869: RADIUS Extensions

l          RFC 1492: An Access Control Protocol, Sometimes Called TACACS

AAA Configuration Task List

The basic procedure to configure AAA is as follows:

1)        Configure the required AAA schemes.

l          Local authentication: Configure local users and related attributes, including usernames and passwords of the users to be authenticated.

l          Remote authentication: Configure the required RADIUS, and/or HWTACACS schemes, and configure user attributes on the servers accordingly.

2)        Configure the AAA methods: Reference the configured AAA schemes in the users’ ISP domains.

l          Authentication method: No authentication (none), local authentication (local), or remote authentication (scheme)

l          Authorization method: No authorization (none) , local authorization (local), or remote authorization (scheme)

l          Accounting method: No accounting (none), local accounting (local), or remote accounting (scheme)

 

 

AAA Configuration Task List

Task	Remarks
Creating an ISP Domain	Required
Configuring ISP Domain Attributes	Optional
Configuring AAA Authentication Methods for an ISP Domain	Required For local authentication, refer to Configuring Local User Attributes. For RADIUS authentication, refer to Configuring RADIUS. For HWTACACS authentication, refer to Configuring HWTACACS.
Configuring AAA Authorization Methods for an ISP Domain	Optional
Configuring AAA Accounting Methods for an ISP Domain	Optional
Configuring Local User Attributes	Optional
Configuring User Group Attributes	Optional
Tearing down User Connections Forcibly	Optional
Configuring the Local EAP Authentication Server	Optional
Displaying and Maintaining AAA	Optional

 

RADIUS Configuration Task List

Task	Remarks
Creating a RADIUS Scheme	Required
Specifying the RADIUS Authentication/Authorization Servers	Required
Specifying the RADIUS Accounting Servers and Relevant Parameters	Optional
Setting the Shared Key for RADIUS Packets	Required
Setting the Upper Limit of RADIUS Request Retransmission Attempts	Optional
Setting the Supported RADIUS Server Type	Optional
Setting the Status of RADIUS Servers	Optional
Configuring Attributes Related to Data to Be Sent to the RADIUS Server	Optional
Setting Timers Regarding RADIUS Servers	Optional
Configuring RADIUS Accounting-On	Optional
Enabling the Listening Port of the RADIUS Client	Optional
Configuring the RADIUS Offload Feature	Optional
Displaying and Maintaining RADIUS	Optional

 

HWTACACS Configuration Task List

Task	Remarks
Creating a HWTACACS scheme	Required
Specifying the HWTACACS Authentication Servers	Required
Specifying the HWTACACS Authorization Servers	Optional
Specifying the HWTACACS Accounting Servers	Optional
Setting the Shared Key for HWTACACS Packets	Required
Configuring Attributes Related to the Data Sent to HWTACACS Server	Optional
Setting Timers Regarding HWTACACS Servers	Optional
Displaying and Maintaining HWTACACS	Optional

 

Configuring AAA

By configuring AAA, you can provide network access service for legal users, protect the networking devices, and avoid unauthorized access and repudiation. In addition, you can configure ISP domains to perform AAA on accessing users.

In AAA, users are divided into LAN users (such as 802.1x users and MAC authentication users), login users (such as SSH, Telnet, FTP, and terminal access users), and command line users (that is, command line authentication users). Except for command line users, you can configure separate authentication/authorization/accounting policies for all the other types of users. Command line users can be configured with authorization policy independently.

Configuration Prerequisites

For remote authentication, authorization, or accounting, you must create the RADIUS or HWTACACS scheme first. For RADIUS scheme configuration, refer to Configuring RADIUS. For HWTACACS scheme configuration, refer to Configuring HWTACACS.

Creating an ISP Domain

An Internet service provider (ISP) domain represents a group of users belonging to it. For a username in the userid@isp-name format, the access device considers the userid part the username for authentication and the isp-name part the ISP domain name.

In a networking scenario with multiple ISPs, an access device may connect users of different ISPs. As users of different ISPs may have different user attributes (such as username and password structure, service type, and rights), you need to configure ISP domains to distinguish the users. In addition, you need to configure different attribute sets including AAA methods for the ISP domains.

For the NAS, each user belongs to an ISP domain. Up to 16 ISP domains can be configured on a NAS. If a user does not provide the ISP domain name, the system considers that the user belongs to the default ISP domain.

Follow these steps to create an ISP domain:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create an ISP domain and enter ISP domain view	domain isp-name	Required
Return to system view	quit	—
Specify the default ISP domain	domain default enable isp-name	Optional By default, the system has a default ISP domain named system.

 

 

Configuring ISP Domain Attributes

Follow these steps to configure ISP domain attributes:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create an ISP domain and enter ISP domain view	domain isp-name	Required
Place the ISP domain to the state of active or blocked	state { active | block }	Optional When created, an ISP domain is in the active state by default, and users in the domain can request network services.
Specify the maximum number of active users in the ISP domain	access-limit enable max-user-number	Optional No limit by default
Configure the idle cut function	idle-cut enable minute	Optional Disabled by default Currently, this command is effective only for LAN users.
Configure the self-service server localization function	self-service-url enable url-string	Optional Disabled by default

 

 

Configuring AAA Authentication Methods for an ISP Domain

In AAA, authentication, authorization, and accounting are separate processes. Authentication refers to the interactive authentication process of username/password/user information during access or service request. The authentication process neither sends authorization information to a supplicant nor triggers any accounting.

AAA supports the following authentication methods:

l          No authentication: All users are trusted and no authentication is performed. Generally, this method is not recommended.

l          Local authentication: Authentication is performed by the NAS, which is configured with the user information, including the usernames, passwords, and attributes. Local authentication features high speed and low cost, but the amount of information that can be stored is limited by the hardware.

l          Remote authentication: The access device cooperates with a RADIUS, or HWTACACS server to authenticate users. As for RADIUS, the device can use the standard RADIUS protocol or extended RADIUS protocol in collaboration with systems like CAMS to implement user authentication. Remote authentication features centralized information management, high capacity, high reliability, and support for centralized authentication for multiple devices. You can configure local authentication as the backup method in case the remote server is not available.

You can configure AAA authentication to work alone without authorization and accounting. By default, an ISP domain uses the local authentication method.

Before configuring authentication methods, complete these three tasks:

l          For RADIUS, or HWTACACS authentication, configure the RADIUS, or HWTACACS scheme to be referenced first. The local and none authentication methods do not require any scheme.

l          Determine the access mode or service type to be configured. With AAA, you can configure an authentication method specifically for each access mode and service type, limiting the authentication protocols that can be used for access.

l          Determine whether to configure an authentication method for all access modes or service types.

Follow these steps to configure AAA authentication methods for an ISP domain:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create an ISP domain and enter ISP domain view	domain isp-name	Required
Specify the default authentication method for all types of users	authentication default { hwtacacs-scheme hwtacacs-scheme-name [ local ] | local | none | radius-scheme radius-scheme-name [ local ] }	Optional local by default
Specify the authentication method for LAN users	authentication lan-access { local | none | radius-scheme radius-scheme-name [ local ] }	Optional The default authentication method is used by default.
Specify the authentication method for login users	authentication login { hwtacacs-scheme hwtacacs-scheme-name [ local ] | local | none | radius-scheme radius-scheme-name [ local ] }	Optional The default authentication method is used by default.

 

 

Configuring AAA Authorization Methods for an ISP Domain

In AAA, authorization is a separate process at the same level as authentication and accounting. Its responsibility is to send authorization requests to the specified authorization server and to send authorization information to users. Authorization method configuration is optional in AAA configuration.

AAA supports the following authorization methods:

l          No authorization: No authorization exchange is performed. Every user is trusted and has the corresponding default rights of the system.

l          Local authorization: Users are authorized by the access device according to the attributes configured for them.

l          Remote authorization: The access device cooperates with a RADIUS or HWTACACS server to authorize users. RADIUS authorization is bound with RADIUS authentication. RADIUS authorization can work only after RADIUS authentication is successful, and the authorization information is carried in the Access-Accept message. HWTACACS authorization is separate from HWTACACS authentication, and the authorization information is carried in the authorization response after successful authentication. You can configure local authorization or no authorization as the backup method in case the remote server is not available.

By default, an ISP domain uses the local authorization method. If the no authorization method (none) is configured, the users are not required to be authorized, in which case an authenticated user has the default right. The default right is visiting (the lowest one) for EXEC users (that is, console users who use the console, AUX, asynchronous serial port, or Telnet to connect to the device, such as Telnet or SSH users. Each connection of these types is called an EXEC user). The default right for FTP users is to use the root directory of the device.

Before configuring authorization methods, complete these three tasks:

1)        For HWTACACS authorization, configure the HWTACACS scheme to be referenced first. For RADIUS authorization, the RADIUS authorization scheme must be the same as the RADIUS authentication scheme; otherwise, it does not take effect.

2)        Determine the access mode or service type to be configured. With AAA, you can configure an authorization scheme specifically for each access mode and service type, limiting the authorization protocols that can be used for access.

3)        Determine whether to configure an authorization method for all access modes or service types.

Follow these steps to configure AAA authorization methods for an ISP domain:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create an ISP domain and enter ISP domain view	domain isp-name	Required
Specify the default authorization method for all types of users	authorization default { hwtacacs-scheme hwtacacs-scheme-name [ local ] | local | none | radius-scheme radius-scheme-name [ local ] }	Optional local by default
Specify the authorization method for command line users	authorization command { hwtacacs-scheme hwtacacs-scheme-name [ local | none ] | local | none }	Optional The default authorization method is used by default.
Specify the authorization method for LAN users	authorization lan-access { local | none | radius-scheme radius-scheme-name [ local ] }	Optional The default authorization method is used by default.
Specify the authorization method for login users	authorization login { hwtacacs-scheme hwtacacs-scheme-name [ local ] | local | none | radius-scheme radius-scheme-name [ local ] }	Optional The default authorization method is used by default.

 

 

Configuring AAA Accounting Methods for an ISP Domain

In AAA, accounting is a separate process at the same level as authentication and authorization. Its responsibility is to send accounting start/update/end requests to the specified accounting server. Accounting is not required, and therefore accounting method configuration is optional.

AAA supports the following accounting methods:

l          No accounting: The system does not perform accounting for the users.

l          Local accounting: Local accounting is implemented on the access device. It is for collecting statistics on the number of users and controlling the number of local user connections; it does not provide statistics for user charge.

l          Remote accounting: The access device cooperates with a RADIUS server or HWTACACS server for accounting of users. You can configure local accounting as the backup method in case the remote server is not available.

By default, an ISP domain uses the local accounting method.

Before configuring accounting methods, complete these three tasks:

1)        For RADIUS or HWTACACS accounting, configure the RADIUS or HWTACACS scheme to be referenced first. The local and none authentication methods do not require any scheme.

2)        Determine the access mode or service type to be configured. With AAA, you can configure an accounting method specifically for each access mode and service type, limiting the accounting protocols that can be used for access.

3)        Determine whether to configure an accounting method for all access modes or service types.

Follow these steps to configure AAA accounting methods for an ISP domain:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create an ISP domain and enter ISP domain view	domain isp-name	Required
Enable the accounting optional feature	accounting optional	Optional Disabled by default
Specify the default accounting method for all types of users	accounting default { hwtacacs-scheme hwtacacs-scheme-name [ local ] | local | none | radius-scheme radius-scheme-name [ local ] }	Optional local by default
Specify the accounting method for LAN users	accounting lan-access { local | none | radius-scheme radius-scheme-name [ local ] }	Optional The default accounting method is used by default.
Specify the accounting method for login users	accounting login { hwtacacs-scheme hwtacacs-scheme-name [ local ] | local | none | radius-scheme radius-scheme-name [ local ] }	Optional The default accounting method is used by default.

 

 

Configuring Local User Attributes

For local authentication, you need to create local users and configure user attributes on the device as needed.

A local user represents a set of user attributes configured on a device and is uniquely identified by the username. For a user requesting a network service to pass local authentication, you must add an entry as required in the local user database of the device.

Each local user belongs to a local user group and bears all attributes of the group, such as authorization attributes. For details about local user group, refer to Configuring User Group Attributes.

When configuring local users and local user groups, pay attention to the effective ranges and priority relationship of user group attributes and user attributes:

l          Authorization attributes

You can configure an authorization attribute in user group view or local user view, making the attribute effective on all local users of the group or only the local user. An authorization attribute configured in local user view takes precedence over the same attribute configured in user group view.

Follow these steps to configure the attributes for a local user:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set the password display mode for all local users	local-user password-display-mode { auto | cipher-force }	Optional auto by default, indicating to display the password of a local user in the way indicated by the password command.
Add a local user and enter local user view	local-user user-name	Required No local user exists by default.
Configure a password for the local user	password { cipher | simple } password	Optional
Place the local user to the state of active or blocked	state { active | block }	Optional When created, a local user is in the state of active by default, and the user can request network services.
Set the maximum number of user connections using the local user account	access-limit max-user-number	Optional By default, there is no limit on the maximum number of user connections using the same local user account.
Specify the service types for the local user	service-type { ftp | lan-access | { ssh | telnet | terminal } * }	Optional By default, no service is authorized to a user.
Configure the binding attributes for the local user	bind-attribute { call-number call-number [ : subcall-number ] | ip ip-address | location port slot-number subslot-number port-number | mac mac-address | vlan vlan-id } *	Optional By default, no binding attribute is configured for a local user.
Configure the authorization attributes for the local user	authorization-attribute { acl acl-number | callback-number callback-number | idle-cut minute | level level | user-profile profile-name | vlan vlan-id | work-directory directory-name } *	Optional By default, no authorization attribute is configured for a local user.
Set the expiration time of the user	expiration-date time	Optional Not set by default
Specify the user group for the local user	group group-name	Optional By default, a local user belongs to default user group system.

 

Note that:

l          With the local-user password-display-mode cipher-force command configured, a local user password is always displayed in cipher text, regardless of the configuration of the password command. In this case, if you use the save command to save the configuration, all existing local user passwords will still be displayed in cipher text after the device restarts, even if you restore the display mode to auto.

l          The access-limit command configured for a local user takes effect only when local accounting is used.

l          Local authentication checks the service types of a local user. If the service types are not available, the user cannot pass authentication.

l          In the authentication method that requires the username and password, including local authentication, RADIUS authentication, and HWTACACS authentication, the commands that a login user can use after logging in depend on the level of the user. In other authentication methods, which commands are available depends on the level of the user interface. For an SSH user using public key authentication, the commands that can be used depend on the level configured on the user interface. For details regarding authentication method and commands accessible to user interface, refer to Login Configuration.

l          Binding attributes are checked upon authentication of a local user. If the checking fails, the user fails the authentication. Therefore, be cautious when deciding which binding attributes should be configured for a local user.

l          Every configurable authorization attribute has its definite application environments and purposes. Therefore, when configuring authorization attributes for a local user, consider what attributes are needed.

Configuring User Group Attributes

For simplification of local user configuration and manageability of local users, the concept of user group is introduced. A user group consists of a group of local users and has a set of local user attributes. You can configure local user attributes for a user group to implement centralized management of user attributes for the local users in the group. Currently, you can configure authorization attributes for a user group.

By default, every newly added local user belongs to a user group named system and bears all attributes of the group. User group system is automatically created by the device.

Follow these steps to configure the attributes for a user group:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a user group and enter user group view	user-group group-name	Required
Configure the authorization attributes for the user group	authorization-attribute { acl acl-number | callback-number callback-number | idle-cut minute | level level | user-profile profile-name | vlan vlan-id | work-directory directory-name } *	Optional By default, no authorization attribute is configured for a user group.

 

Tearing down User Connections Forcibly

Follow these steps to tear down user connections forcibly:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Tear down AAA user connections forcibly	cut connection { all | domain isp-name | ucibindex ucib-index | user-name user-name }	Required Applies to only LAN access user connections at present

 

Configuring the Local EAP Authentication Server

In some simple application environments, you may prefer local authentication by the access device to AAA server-based authentication. In this case, if the access authentication method is the Extensible Authentication Protocol (EAP, which is frequently used in wireless environments), you need to configure the local EAP authentication server on the access device to cooperate with the AAA local authentication method for local EAP authentication.

In addition, the RADIUS offload feature used when the remote RADIUS server does not support EAP authentication needs the cooperation of the local EAP authentication server. For details, refer to Configuring the RADIUS Offload Feature.

You can configure the local EAP authentication server by specifying the EAP profile for the local authentication server (that is, the access device) in system view. An EAP profile is a collection of local EAP authentication settings, including the authentication method to be used and, for some authentication methods, the SSL server policy to be referenced.

Follow these steps to configure the local EAP authentication server:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create an EAP profile and enter EAP profile view	eap-profile profile-name	Required
Specify the EAP authentication method	method { md5 | peap-mschapv2 | tls }	Required By default, no EAP authentication method is specified for an EAP profile.
Specify the SSL server policy for EAP authentication	ssl-server-policy policy-name	Optional By default, no SSL server policy is specified for an EAP profile.
Return to system view	quit	—
Specify the EAP profile for the local authentication server	local-server authentication eap-profile profile-name	Required

 

 

Displaying and Maintaining AAA

To do…	Use the command…	Remarks
Display the configuration information of a specified ISP domain or all ISP domains	display domain [ isp-name ]	Available in any view
Display information about specified or all user connections	display connection [ domain isp-name | ucibindex ucib-index | user-name user-name ]	Available in any view
Display information about specified or all local users	display local-user [ idle-cut { disable | enable } | service-type { ftp | lan-access | ssh | telnet | terminal } | state { active | block } | user-name user-name | vlan vlan-id ]	Available in any view
Display configuration information about a specified user group or all user groups	display user-group [ group-name ]	Available in any view

 

Configuring RADIUS

The RADIUS protocol is configured on a per scheme basis. After creating a RADIUS scheme, you need to configure the IP addresses and UDP ports of the RADIUS servers for the scheme. The servers include authentication/authorization servers and accounting servers, or primary servers and secondary servers. In other words, the attributes of a RADIUS scheme mainly include IP addresses of primary and secondary servers, shared key, and RADIUS server type.

Actually, the RADIUS protocol configurations only set the parameters necessary for the information interaction between a NAS and a RADIUS server. For these settings to take effect, you must reference the RADIUS scheme containing those settings in ISP domain view. For information about the commands for referencing a scheme, refer to Configuring AAA.

 

 

Creating a RADIUS Scheme

Before performing other RADIUS configurations, follow these steps to create a RADIUS scheme and enter RADIUS scheme view:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default

 

 

Specifying the RADIUS Authentication/Authorization Servers

Follow these steps to specify the RADIUS authentication/authorization servers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Specify the primary RADIUS authentication/authorization server	primary authentication ip-address [ port-number ]	Required Configure at least one of the commands No authentication server by default
Specify the secondary RADIUS authentication/authorization server	secondary authentication ip-address [ port-number ]

 

 

Specifying the RADIUS Accounting Servers and Relevant Parameters

Follow these steps to specify the RADIUS accounting servers and perform related configurations:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Specify the primary RADIUS accounting server	primary accounting ip-address [ port-number ]	Required Configure at least one of the commands No accounting server by default
Specify the secondary RADIUS accounting server	secondary accounting ip-address [ port-number ]
Enable the device to buffer stop-accounting requests getting no responses	stop-accounting-buffer enable	Optional Enabled by default
Set the maximum number of stop-accounting request transmission attempts	retry stop-accounting retry-times	Optional 500 by default
Set the maximum number of accounting request transmission attempts	retry realtime-accounting retry-times	Optional 5 by default

 

 

Setting the Shared Key for RADIUS Packets

The RADIUS client and RADIUS server use the MD5 algorithm to encrypt packets exchanged between them and a shared key to verify the packets. Only when the same key is used can they properly receive the packets and make responses.

Follow these steps to set the shared key for RADIUS packets:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Set the shared key for RADIUS authentication/authorization or accounting packets	key { accounting | authentication } string	Required No key by default

 

 

Setting the Upper Limit of RADIUS Request Retransmission Attempts

Because RADIUS uses UDP packets to carry data, the communication process is not reliable. If a NAS receives no response from the RADIUS server before the response timeout timer expires, it is required to retransmit the RADIUS request. If the number of transmission attempts exceeds the specified limit but it still receives no response, it considers that the authentication has failed.

Follow these steps to set the upper limit of RADIUS request retransmission attempts:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Set the number of retransmission attempts of RADIUS packets	retry retry-times	Optional 3 by default

 

 

Setting the Supported RADIUS Server Type

Follow these steps to set the supported RADIUS server type:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Specify the RADIUS server type supported by the device	server-type { extended | standard }	Optional By default, the supported RADIUS server type is standard.

 

 

Setting the Status of RADIUS Servers

When a primary server fails, the device automatically tries to communicate with the secondary server.

When both the primary and secondary servers are available, the device sends request packets to the primary server.

Once the primary server fails, the primary server turns into the state of block, and the device turns to the secondary server. In this case:

l          If the secondary server is available, the device triggers the primary server quiet timer. After the quiet timer times out, the status of the primary server is active again and the status of the secondary server remains the same.

l          If the secondary server fails, the device restores the status of the primary server to active immediately.

If the primary server has resumed, the device turns to use the primary server and stops communicating with the secondary server. After accounting starts, the communication between the client and the secondary server remains unchanged.

Follow these steps to set the status of RADIUS servers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Set the status of the primary RADIUS authentication/authorization server	state primary authentication { active | block }	Optional active for every server configured with IP address in the RADIUS scheme
Set the status of the primary RADIUS accounting server	state primary accounting { active | block }
Set the status of the secondary RADIUS authentication/authorization server	state secondary authentication { active | block }
Set the status of the secondary RADIUS accounting server	state secondary accounting { active | block }

 

 

Configuring Attributes Related to Data to Be Sent to the RADIUS Server

Follow these steps to configure the attributes related to data to be sent to the RADIUS server:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enable the RADIUS trap function		radius trap { accounting-server-down | authentication-server-down }	Optional Disabled by default
Create a RADIUS scheme and enter RADIUS scheme view		radius scheme radius-scheme-name	Required Not defined by default
Specify the format of the username to be sent to a RADIUS server		user-name-format { keep-original | with-domain | without-domain }	Optional By default, the ISP domain name is included in the username.
Specify the unit for data flows or packets to be sent to a RADIUS server		data-flow-format { data { byte | giga-byte | kilo-byte | mega-byte } | packet { giga-packet | kilo-packet | mega-packet | one-packet } }*	Optional The defaults are as follows: byte for data flows, and one-packet for data packets.
Set the source IP address of the device to send RADIUS packets	In RADIUS scheme view	nas-ip ip-address	Use either command By default, a RADIUS scheme uses the source IP address specified in system view; there is no source IP address specified for RADIUS packets and the IP address of the interface for sending the RADIUS packets will be used as the source IP address of the RADIUS packets.
	In system view	quit
		radius nas-ip ip-address

 

 

Setting Timers Regarding RADIUS Servers

When communicating with the RADIUS server, a device can enable the following three timers:

l          RADIUS server response timeout (response-timeout): If a NAS receives no response from the RADIUS server in a period of time after sending a RADIUS request (authentication/authorization or accounting request), it has to resend the request so that the user has more opportunity to obtain the RADIUS service. The NAS uses the RADIUS server response timeout timer to control the transmission interval.

l          Primary server quiet timer (timer quiet): If the primary server is not reachable, its state changes to blocked, and the device will turn to the specified secondary server. If the secondary server is reachable, the device starts this timer and communicates with the secondary server. After this timer expires, the device turns the state of the primary server to active and tries to communicate with the primary server while keeping the state of the secondary server unchanged. If the primary server has come back into operation, the device interacts with the primary server and terminates its communication with the secondary server.  

l          Real-time accounting interval (realtime-accounting): This timer defines the interval for performing real-time accounting of users. After this timer is set, the switch will send accounting information of online users to the RADIUS server at the specified interval.

Follow these steps to set timers regarding RADIUS servers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter RADIUS scheme view	radius scheme radius-scheme-name	Required Not defined by default
Set the RADIUS server response timeout timer	timer response-timeout seconds	Optional 3 seconds by default
Set the quiet timer for the primary server	timer quiet minutes	Optional 5 minutes by default
Set the real-time accounting interval	timer realtime-accounting minutes	Optional 12 minutes by default

 

 

Configuring RADIUS Accounting-On

With the accounting-on function enabled, a device sends, whenever it reboots, accounting-on packets to the RADIUS server, requesting the server to log out its users. This solves the problem that users online before the reboot cannot re-log in after the reboot.

Once configured, the accounting-on function is executed as soon as the device restarts and recovers its configuration. In case that the majority of the RADIUS servers specified on a device fail to respond to the accounting-on packets, the number of accounting-on packet retransmission attempts is too big, or the accounting-on packet retransmission interval is too long, the device will not handle AAA services until all these packets are retransmitted and all RADIUS servers have responded to accounting-on packets.

Follow these steps to configure accounting-on function of a RADIUS server:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create RADIUS scheme and enter its view	radius scheme radius-scheme-name	Required Not defined by default
Enable accounting-on	accounting-on enable	Required Disabled by default
Set the number of accounting-on packet retransmission attempts	accounting-on enable send send-times	Optional 5 times by default
Set the retransmission  interval of accounting-on packets	accounting-on enable interval seconds	Optional 3 seconds by default

 

 

Enabling the Listening Port of the RADIUS Client

Follow these steps to enable the listening port of the RADIUS client:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Enable the listening port of the RADIUS client	radius client enable	Optional Enabled by default

 

Configuring the RADIUS Offload Feature

Some RADIUS servers do not support EAP authentication, that is, they cannot process EAP packets. If this is the case, the access device needs to process EAP packets from clients before forwarding them to the server. A feature called RADIUS offload is introduced for this purpose.

The RADIUS offload feature needs the cooperation of the local EAP authentication server and works together with the local EAP authentication server as follows:

1)        Upon receiving EAP packets, the local EAP authentication server transforms the contained authentication information into corresponding RADIUS attributes, and then encapsulates and sends the attributes in RADIUS authentication requests to the RADIUS servers for authentication.

2)        When the RADIUS server receives the requests, it resolves the authentication information in the requests, performs authentication, and then encapsulates and sends the authentication results in RADIUS packets to the local EAP authentication server.

To deploy the RADIUS offload feature, you need to perform the following configurations on the access device:

1)        Configuring the local EAP authentication server, specifying the EAP authentication method as PEAP-MSCHAPv2. For configuration details, refer to Configuring the Local EAP Authentication Server.

2)        Configuring the EAP offload feature. You can do so by configuring EAP offload for the RADIUS schemes.

Follow these steps to configure the EAP offload feature:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a RADIUS scheme and enter its view	radius scheme radius-scheme-name	Required By default, no RADIUS scheme is present.
Configure the EAP offload feature	eap offload method peap-mschapv2	Required Not configured by default

 

After the above configurations take effect, when the access device uses the RADIUS scheme for EAP authentication of a client, PEAP-MSCHAPv2 authentication is performed between the client and access device, and RADIUS packet carrying the MS-CHAPv2 attribute is used for authentication exchange between the access device and RADIUS server.

Note that only PEAP-MSCHAPv2 authentication supports the EAP offload feature at present.

Displaying and Maintaining RADIUS

To do…	Use the command…	Remarks
Display the configuration information of a specified RADIUS scheme or all RADIUS schemes	display radius scheme [ radius-scheme-name ]	Available in any view
Display statistics about RADIUS packets	display radius statistics	Available in any view
Display information about buffered stop-accounting requests that get no responses	display stop-accounting-buffer { radius-scheme radius-server-name | session-id session-id | time-range start-time stop-time | user-name user-name }	Available in any view
Clear RADIUS statistics	reset radius statistics	Available in user view
Clear buffered stop-accounting requests that get no responses	reset stop-accounting-buffer { radius-scheme radius-server-name | session-id session-id | time-range start-time stop-time | user-name user-name }	Available in user view

 

Configuring HWTACACS

 

Creating a HWTACACS scheme

The HWTACACS protocol is configured on a per scheme basis. Before performing other HWTACACS configurations, follow these steps to create a HWTACACS scheme and enter HWTACACS scheme view:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view	hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default

 

 

Specifying the HWTACACS Authentication Servers

Follow these steps to specify the HWTACACS authentication servers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view	hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default
Specify the primary HWTACACS authentication server	primary authentication ip-address [ port-number ]	Required Configure at least one of the commands No authentication server by default
Specify the secondary HWTACACS authentication server	secondary authentication ip-address [ port-number ]

 

 

Specifying the HWTACACS Authorization Servers

Follow these steps to specify the HWTACACS authorization servers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view	hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default
Specify the primary HWTACACS authorization server	primary authorization ip-address [ port-number ]	Required Configure at least one of the commands No authorization server by default
Specify the secondary HWTACACS authorization server	secondary authorization ip-address [ port-number ]

 

 

Specifying the HWTACACS Accounting Servers

Follow these steps to specify the HWTACACS accounting servers and perform related configurations:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view	hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default
Specify the primary HWTACACS accounting server	primary accounting ip-address [ port-number ]	Required Configure at least one of the commands No accounting server by default
Specify the secondary HWTACACS accounting server	secondary accounting ip-address [ port-number ]
Enable the device to buffer stop-accounting requests getting no responses	stop-accounting-buffer enable	Optional Enabled by default
Set the maximum number of stop-accounting request transmission attempts	retry stop-accounting retry-times	Optional 100 by default

 

 

Setting the Shared Key for HWTACACS Packets

When using a HWTACACS server as an AAA server, you can set a key to secure the communications between the device and the HWTACACS server.

The HWTACACS client and HWTACACS server use the MD5 algorithm to encrypt packets exchanged between them and a shared key to verify the packets. Only when the same key is used can they properly receive the packets and make responses.

Follow these steps to set the shared key for HWTACACS packets:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view	hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default
Set the shared keys for HWTACACS authentication, authorization, and accounting packets	key { accounting | authentication | authorization } string	Required No shared key exists by default.

 

Configuring Attributes Related to the Data Sent to HWTACACS Server

Follow these steps to configure the attributes related to the data sent to the HWTACACS server:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view		hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default
Specify the format of the username to be sent to a HWTACACS server		user-name-format { keep-original | with-domain | without-domain }	Optional By default, the ISP domain name is included in the username.
Specify the unit for data flows or packets to be sent to a HWTACACS server		data-flow-format { data { byte | giga-byte | kilo-byte | mega-byte } | packet { giga-packet | kilo-packet | mega-packet | one-packet } }*	Optional The defaults are as follows: byte for data flows, and one-packet for data packets.
Set the source IP address of the device to send HWTACACS packets	In HWTACACS scheme view	nas-ip ip-address	Use either command By default, the outbound port serves as the source IP address to send HWTACACS packets.
	In system view	quit
		hwtacacs nas-ip ip-address

 

 

Setting Timers Regarding HWTACACS Servers

Follow these steps to set timers regarding HWTACACS servers:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Create a HWTACACS scheme and enter HWTACACS scheme view	hwtacacs scheme hwtacacs-scheme-name	Required Not defined by default
Set the HWTACACS server response timeout timer	timer response-timeout seconds	Optional 5 seconds by default
Set the quiet timer for the primary server	timer quiet minutes	Optional 5 minutes by default
Set the real-time accounting interval	timer realtime-accounting minutes	Optional 12 minutes by default

 

 

Displaying and Maintaining HWTACACS

To do…	Use the command…	Remarks
Display configuration information or statistics of the specified or all HWTACACS schemes	display hwtacacs [ hwtacacs-server-name [ statistics ] ]	Available in any view
Display information about buffered stop-accounting requests that get no responses	display stop-accounting-buffer hwtacacs-scheme hwtacacs-scheme-name	Available in any view
Clear HWTACACS statistics	reset hwtacacs statistics { accounting | all | authentication | authorization }	Available in user view
Clear buffered stop-accounting requests that get no responses	reset stop-accounting-buffer hwtacacs-scheme hwtacacs-scheme-name	Available in user view

 

AAA Configuration Examples

AAA for Telnet Users by a HWTACACS Server

Network requirements

As shown in Figure 1-7, configure the switch to use the HWTACACS server to provide authentication, authorization, and accounting services to login users.

l          The HWTACACS server is used for authentication, authentication, and accounting. Its IP address is 10.1.1.1.

l          On the switch, set the shared keys for authentication, authorization, and accounting packets to expert. Configure the switch to remove the domain name from a user name before sending the user name to the HWTACACS server.

l          On the HWTACACS server, set the shared keys for packets exchanged with the switch to expert.

Figure 1-7 Configure AAA for Telnet users by a HWTACACS server

 

Configuration procedure

# Configure the IP addresses of the interfaces (omitted).

# Enable the Telnet server on the switch.

<Switch> system-view

[Switch] telnet server enable

# Configure the switch to use AAA for Telnet users.

[Switch] user-interface vty 0 4

[Switch-ui-vty0-4] authentication-mode scheme

[Switch-ui-vty0-4] quit

# Configure the HWTACACS scheme.

[Switch] hwtacacs scheme hwtac

[Switch-hwtacacs-hwtac] primary authentication 10.1.1.1 49

[Switch-hwtacacs-hwtac] primary authorization 10.1.1.1 49

[Switch-hwtacacs-hwtac] primary accounting 10.1.1.1 49

[Switch-hwtacacs-hwtac] key authentication expert

[Switch-hwtacacs-hwtac] key authorization expert

[Switch-hwtacacs-hwtac] key accounting expert

[Switch-hwtacacs-hwtac] user-name-format without-domain

[Switch-hwtacacs-hwtac] quit

# Configure the AAA methods for the domain.

[Switch] domain bbb

[Switch-isp-bbb] authentication login hwtacacs-scheme hwtac

[Switch-isp-bbb] authorization login hwtacacs-scheme hwtac

[Switch-isp-bbb] accounting login hwtacacs-scheme hwtac

[Switch-isp-bbb] quit

# You can achieve the same result by setting default AAA methods for all types of users.

[Switch] domain bbb

[Switch-isp-bbb] authentication default hwtacacs-scheme hwtac

[Switch-isp-bbb] authorization default hwtacacs-scheme hwtac

[Switch-isp-bbb] accounting default hwtacacs-scheme hwtac

When telneting into the switch, a user enters username userid@bbb for authentication using domain bbb.

AAA for Telnet Users by Separate Servers

Network requirements

As shown in Figure 1-8, configure the switch to provide local authentication, HWTACACS authorization, and RADIUS accounting services to Telnet users. The user name and the password for Telnet users are both hello.

l          The HWTACACS server is used for authorization. Its IP address is 10.1.1.2. On the switch, set the shared keys for packets exchanged with the HWTACACS server to expert. Configure the switch to remove the domain name from a user name before sending the user name to the HWTACACS server.

l          The RADIUS server is used for accounting. Its IP address is 10.1.1.1. On the switch, set the shared keys for packets exchanged with the RADIUS server to expert.

 

 

Figure 1-8 Configure AAA by separate servers for Telnet users

 

Configuration procedure

# Configure the IP addresses of various interfaces (omitted).

# Enable the Telnet server on the switch.

<Switch> system-view

[Switch] telnet server enable

# Configure the switch to use AAA for Telnet users.

[Switch] user-interface vty 0 4

[Switch-ui-vty0-4] authentication-mode scheme

[Switch-ui-vty0-4] quit

# Configure the HWTACACS scheme.

[Switch] hwtacacs scheme hwtac

[Switch-hwtacacs-hwtac] primary authorization 10.1.1.2 49

[Switch-hwtacacs-hwtac] key authorization expert

[Switch-hwtacacs-hwtac] user-name-format without-domain

[Switch-hwtacacs-hwtac] quit

# Configure the RADIUS scheme.

[Switch] radius scheme rd

[Switch-radius-rd] primary accounting 10.1.1.1 1813

[Switch-radius-rd] key accounting expert

[Switch-radius-rd] server-type extended

[Switch-radius-rd] user-name-format without-domain

[Switch-radius-rd] quit

# Create a local user named hello.

[Switch] local-user hello

[Switch-luser-hello] service-type telnet

[Switch-luser-hello] password simple hello

[Switch-luser-hello] quit

# Configure the AAA methods for the ISP domain.

[Switch] domain bbb

[Switch-isp-bbb] authentication login local

[Switch-isp-bbb] authorization login hwtacacs-scheme hwtac

[Switch-isp-bbb] accounting login radius-scheme rd

[Switch-isp-bbb] quit

# Configure the default AAA methods for all types of users.

[Switch] domain bbb

[Switch-isp-bbb] authentication default local

[Switch-isp-bbb] authorization default hwtacacs-scheme hwtac

[Switch-isp-bbb] accounting default radius-scheme cams

When telneting into the switch, a user enters username telnet@bbb for authentication using domain bbb.

AAA for SSH Users by a RADIUS Server

Network requirements

As shown in Figure 1-9, configure the switch to use the RADIUS server to provide authentication, authorization, and accounting services to SSH users.

l          The RADIUS server is responsible for both authentication and accounting. Its IP address is 10.1.1.1.

l          On the switch, set both the shared keys for authentication and accounting packets to expert; and specify that the usernames sent to the RADIUS server carry the domain name.

l          The RADIUS server runs the CAMS server.

Figure 1-9 Configure AAA for SSH users by a RADIUS server

 

Configuration procedure

1)        Configure the RADIUS server.

 

 

# Add an access device.

Log into the CAMS management platform and select System Management > System Configuration from the navigation tree. In the System Configuration window, click Modify of the Access Device item, and then click Add to enter the Add Access Device window and perform the following configurations:

l          Specify the IP address of the switch as 10.1.1.2

l          Set both the shared keys for authentication and accounting packets to expert

l          Select Device Management Service as the service type

l          Specify the ports for authentication and accounting as 1812 and 1813 respectively

l          Select Extensible Protocol as the protocol type

l          Select Standard as the RADIUS packet type

Figure 1-10 Add an access device

 

# Add a user for device management

From the navigation tree, select User Management > User for Device Management, and then in the right pane, click Add to enter the Add Account window and perform the following configurations:

l          Add a user named hello@bbb, and specify the password

l          Select SSH as the service type

l          Specify the IP address range of the hosts to be managed

Figure 1-11 Add an account for device management

 

2)        Configure the switch

# Configure the IP address of VLAN interface 2, through which the SSH user accesses the switch.

<Switch> system-view

[Switch] interface vlan-interface 2

[Switch-Vlan-interface2] ip address 192.168.1.70 255.255.255.0

[Switch-Vlan-interface2] quit

# Generate RSA and DSA key pairs and enable the SSH server.

[Switch] public-key local create rsa

[Switch] public-key local create dsa

[Switch] ssh server enable

# Configure the switch to use AAA for SSH users.

[Switch] user-interface vty 0 4

[Switch-ui-vty0-4] authentication-mode scheme

# Configure the user interfaces to support SSH.

[Switch-ui-vty0-4] protocol inbound ssh

[Switch-ui-vty0-4] quit

# Configure the RADIUS scheme.

[Switch] radius scheme rad

[Switch-radius-rad] primary authentication 10.1.1.1 1812

[Switch-radius-rad] primary accounting 10.1.1.1 1813

[Switch-radius-rad] key authentication expert

[Switch-radius-rad] key accounting expert

[Switch-radius-rad] user-name-format with-domain

[Switch-radius-rad] quit

# Configure the AAA methods for the domain.

[Switch] domain bbb

[Switch-isp-bbb] authentication login radius-scheme rad

[Switch-isp-bbb] authorization login radius-scheme rad

[Switch-isp-bbb] accounting login radius-scheme rad

[Switch-isp-bbb] quit

When using SSH to log in, a user enters a username in the form userid@bbb for authentication using domain bbb.

3)        Verify the configuration

After the above configuration, the SSH user should be able to use the configured account to access the user interface of the switch. The commands that the user can access depend on the settings for EXEC users on the CAMS server.

Troubleshooting AAA

Troubleshooting RADIUS

Symptom 1: User authentication/authorization always fails.

Analysis:

1)        A communication failure exists between the NAS and the RADIUS server.

2)        The username is not in the format of userid@isp-name or no default ISP domain is specified for the NAS.

3)        The user is not configured on the RADIUS server.

4)        The password of the user is incorrect.

5)        The RADIUS server and the NAS are configured with different shared key.

Solution:

Check that:

1)        The NAS and the RADIUS server can ping each other.

2)        The username is in the userid@isp-name format and a default ISP domain is specified on the NAS.

3)        The user is configured on the RADIUS server.

4)        The correct password is entered.

5)        The same shared key is configured on both the RADIUS server and the NAS.

Symptom 2: RADIUS packets cannot reach the RADIUS server.

Analysis:

1)        The communication link between the NAS and the RADIUS server is down (at the physical layer and data link layer).

2)        The NAS is not configured with the IP address of the RADIUS server.

3)        The UDP ports for authentication/authorization and accounting are not correct.

4)        The port numbers of the RADIUS server for authentication, authorization and accounting are being used by other applications.

Solution:

Check that:

1)        The communication links between the NAS and the RADIUS server work well at both physical and link layers.

2)        The IP address of the RADIUS server is correctly configured on the NAS.

3)        UDP ports for authentication/authorization/accounting configured on the NAS are the same as those configured on the RADIUS server.

4)        The port numbers of the RADIUS server for authentication, authorization and accounting are available.

Symptom 3: A user is authenticated and authorized, but accounting for the user is not normal.

Analysis:

1)        The accounting port number is not correct.

2)        Configuration of the authentication/authorization server and the accounting server are not correct on the NAS. For example, one server is configured on the NAS to provide all the services of authentication/authorization and accounting, but in fact the services are provided by different servers.

Solution:

Check that:

1)        The accounting port number is correctly set.

2)        The authentication/authorization server and the accounting server are correctly configured on the NAS.

Troubleshooting HWTACACS

Refer to Troubleshooting RADIUS if you encounter a HWTACACS fault.