Cisco Nexus 1000V Security Configuration Guide, Release 4.2(1)SV1(4a)

Configuring AAA

This chapter describes how to configure authentication, authorization, and accounting (AAA) and includes the following sections:

•Information About AAA

•Prerequisites for AAA

•AAA Guidelines and Limitations

•Default Settings

•Configuring AAA

•Verifying AAA Configuration

•Example AAA Configuration

•Additional References

•Feature History for AAA

Information About AAA

This section includes the following topics:

•AAA Security Services

•AAA Server Groups

AAA Security Services

Based on a user ID and password combination, AAA is used to authenticate and authorize users. A key secures communication with AAA servers.

In many circumstances, AAA uses protocols such as RADIUS or TACACS+, to administer its security functions. If your router or access server is acting as a network access server, AAA is the means through which you establish communication between your network access server and your RADIUS or TACACS+, security server.

Although AAA is the primary (and recommended) method for access control, additional features for simple access control are available outside the scope of AAA, such as local username authentication, line password authentication, and enable password authentication. However, these features do not provide the same degree of access control that is possible by using AAA.

Separate AAA configurations are made for the following services:

•User Telnet or Secure Shell (SSH) login authentication

•Console login authentication

•User management session accounting

Table 4-1 shows the related CLI command for configuring an AAA service.

.

AAA secures the following:

•Authentication

•Authorization

•Accounting

Authentication

Authentication identifies users with a login and password, messaging, and encryption.

Authentication is accomplished as follows:

Figure 4-1 Authenticating User Log In

Authorization

Authorization restricts the actions that a user is allowed to perform.

Accounting

Accounting tracks and maintains a log of every SVS management session. You can use this information to generate reports for troubleshooting and auditing purposes. You can store accounting logs locally or send them to remote AAA servers.

AAA Server Groups

Remote AAA server groups can provide fail-over in case one remote AAA server fails to respond. If the first server in the group fails, the next server in the group is tried until a server responds. Multiple server groups can provide fail-over for each other in this same way.

If all remote server groups fail, the local database is used for authentication.

Prerequisites for AAA

Authentication using remote AAA servers requires that the following be in place:

•At least one TACACS+ or RADIUS server is IP reachable

•The VSM is configured as an AAA server client.

•A shared secret key is configured on the VSM and the remote AAA server.

See the "Configuring Shared Keys" procedure on page 6-9.

AAA Guidelines and Limitations

The Cisco Nexus 1000Vdoes not support user names made up of all numeric characters and does not create local user names made up of all numeric characters. If a username made up of all numeric characters exists on an AAA server and is entered during login, the Cisco Nexus 1000V does authenticate the user.

Default Settings

The following table lists the AAA defaults.

Configuring AAA

This section includes the following topics:

•Configuring a Login Authentication Method

•Enabling Login Authentication Failure Messages

Use the following flow chart to configure AAA.

Flow Chart: Configuring AAA

Configuring a Login Authentication Method

Use this procedure to configure the login authentication method.

BEFORE YOU BEGIN

Before beginning this procedure, you must know or do the following:

•You are logged in to the CLI in EXEC mode.

•If authentication is to be done with TACACS+ server group(s), you have already added the group(s). For more information, see Configuring a TACACS+ Server Group, page 6-12.

SUMMARY STEPS

1. config t

2. aaa authentication login {console | default} {group group-list [none] | local | none}

3. exit

4. show aaa authentication

5. copy running-config start-config

DETAILED STEPS

Enabling Login Authentication Failure Messages

Use this procedure to enable the login authentication failure message to displays if the remote AAA servers do not respond.

BEFORE YOU BEGIN

Before beginning this procedure, you must know or do the following:

•You are logged in to the CLI in EXEC mode.

•The following is the Login Authentication Failure message:

Remote AAA servers unreachable; local authentication done.

Remote AAA servers unreachable; local authentication failed.

SUMMARY STEPS

1. config t

2. aaa authentication login error-enable

3. exit

4. show aaa authentication login error-enable

5. copy running-config start-config

DETAILED STEPS

Verifying AAA Configuration

To display AAA configuration information, perform one of the following tasks:

Example 4-1 show aaa authentication

n1000v# show aaa authentication login error-enable 

disabled

Example 4-2 show running config aaa

n1000v# show running-config aaa all

version 4.0(1)

aaa authentication login default local 

aaa accounting default local 

no aaa authentication login error-enable 

no aaa authentication login mschap enable 

no radius-server directed-request 

no snmp-server enable traps aaa server-state-change 

no tacacs-server directed-request

n1000v# 

Example 4-3 show startup-config aaa

n1000v# show startup-config aaa

version 4.0(1)svs# 

Example AAA Configuration

The following is an AAA configuration example:

aaa authentication login default group tacacs

aaa authentication login console group tacacs

Additional References

For additional information related to implementing AAA, see the following sections:

•Related Documents

•Standards

Related Documents

Standards

Feature History for AAA

This section provides the AAA release history.