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CCSP Self-Study: Advanced AAA Security for Cisco Router Networks

  • Sample Chapter is provided courtesy of Cisco Press.
  • Date: May 21, 2004.

Chapter Description

For CCSP candidates, John Roland discusses Cisco Secure ACS 3.0 for Windows 2000/NT Servers, Cisco Secure ACS for UNIX, and the security services of TACACS+, RADIUS, and Kerberos.

Administering and Troubleshooting Cisco Secure ACS for Windows

The Cisco Secure ACS for Windows web browser interface makes administration of AAA features easy. Each of the buttons on the navigational bar (listed next in top-to-bottom order as shown in Figure 3-9) represents a particular area or function that you can configure. Depending on your configuration, you may not need to configure all the areas.

  • User Setup—Add, edit, and delete user accounts, and list users in databases

  • Group Setup—Create, edit, and rename groups, and list all users in a group

Figure 9Figure 3-9 Main Window

  • Shared Profile Components—Develop and name reusable, shared sets of authorization components that may be applied to one or more users or groups of users and referenced by name within individual profiles. Components include network access restrictions (NARs), command authorization sets, and downloadable PIX ACLs.

  • Network Configuration—Configure and edit network access server parameters, add and delete network access servers, and configure AAA server distribution parameters

  • System Configuration—Start and stop Cisco Secure ACS for Windows services, configure logging, control Database Replication, and control RDBMS Synchronization

  • Interface Configuration—Configure user-defined fields that will be recorded in accounting logs, configure TACACS+ and RADIUS options, and control display of options in the user interface

  • Administration Control—Control administration of Cisco Secure ACS for Windows from any workstation on the network

  • External User Databases—Configure the unknown user policy, configure authorization privileges for unknown users, and configure external database types

  • Reports and Activity—View the following information, which is a partial list of the types of reports available to you when you select this button. You can import these files into most database and spreadsheet applications.

    • TACACS+ Accounting Report—Lists when sessions stop and start, records network access server messages with username, provides CLID information, and records the duration of each session

    • RADIUS Accounting Report—Lists when sessions stop and start, records network access server messages with username, provides CLID information, and records the duration of each session

    • Failed Attempts Report—Lists authentication and authorization failures with an indication of the cause

    • Logged in Users—Lists all users who are currently receiving services for a single network access server or all network access servers with access to Cisco Secure ACS for Windows

    • Disabled Accounts—Lists all user accounts that are currently disabled

    • Admin Accounting Report—Lists configuration commands entered on a TACACS+ (Cisco) network access server

  • Online Documentation—Provides more detailed information about the configuration, operation, and concepts of Cisco Secure ACS for Windows

As previously stated, the preceding list represents the order in which the buttons appear on the navigational bar, not the order that you want to follow for configuration. The order to follow for configuration depends on your preferences and needs. One typical order of configuration is as follows:

Step 1


Administration Control—Configure access for remote administrators.

Step 2


Network Configuration—Configure and verify connectivity to a network access server.

Step 3


Group Setup—Configure available options and parameters for specific groups. All users must belong to a group.

Step 4


User Setup—Add users to a group that is configured.

Step 5


Additional configuration—Verify or configure settings in all other necessary areas.

Start troubleshooting Cisco Secure ACS for Windows–related AAA problems by examining the Failed Attempts Report under Reports and Activity, as shown in Figure 3-10. The report shows several types of failures.

Figure 10Figure 3-10 Troubleshooting Grid

Cisco Secure ACS for Windows has debug capabilities that uses a combination of logging files to record debug information. You can view these logging files as reports in order to check for system problems. You can also run CSTacacs, CSRadius, and CSAuth from a DOS command line to see debug information for those services. See the Cisco Tech Notes article at http://www.cisco.com/en/US/products/sw/secursw/ps2086 /products_tech_note09186a00800afec1.shtml for more information on setting debug log levels and using the debug command-line capabilities of the Cisco Secure ACS for Windows service modules.

Authentication Failure

Assuming that Cisco Secure ACS for Windows and the router are communicating and that you are authenticating against the Windows NT or Windows 2000 user database, check the following items if you encounter an authentication failure:

  • Are the username and password being entered correctly? (The password is case sensitive.)

  • Do the username and password exist in the Windows NT or Windows 2000 user database? (Use the Windows 2000 User Manager administration tool to verify the user entry and to reset passwords, if necessary.)

  • Is the dial-in interface on the network access server configured with ppp authentication pap?

  • Is the User Must Change Password at Next Login check box checked in Windows NT or Windows 2000? (Uncheck the check box it if it is checked.)

  • Does the username have the rights to log on locally in the Windows NT or Windows 2000 Server window (Trust Relationship/Domain)?

  • Is Cisco Secure ACS for Windows configured to authenticate against the Windows NT or Windows 2000 user database?

  • Is Cisco Secure ACS for Windows configured to grant dial-in permission to the user?

  • If the username was able to authenticate before and is unable to now, is the account disabled on Windows NT or Windows 2000 or Cisco Secure ACS for Windows?

  • Has the password expired on Windows NT or Windows 2000?

  • Does the username contain an illegal character?

Windows NT or Windows 2000 will send the domain name and username for authentication when a user attempts to access the network through Dial-Up Networking (DUN).

Authorization Failure

If the dial-in user is authenticating, but authorization is failing, check the following:

  • Are the proper network services checked in the Group Settings?

  • If IP is checked, how is the dial-in user obtaining an IP address?

  • Is there an IP pool configured on the network access server?

  • Is the name of the IP pool entered in the Group Settings? (Leave this blank if a default IP pool has been configured.)

  • If authorizing commands, has the aaa authorization commands 1 tacacs+ command been entered into the Cisco IOS configuration? (You can substitute any privilege level from 0 to 15 for the 1 in this command.)

  • Has the radio button for the command been selected?

  • Has the radio button for the argument been selected?

Accounting Failure

If AAA is not working, yet there is no entry in the report, there is an invalid setup between Cisco Secure ACS for Windows and the router. Check the following items to troubleshoot this problem:

  • Can the router ping the Windows NT or Windows 2000 server?

  • Can the Windows NT or Windows 2000 server ping the router?

  • Is the TACACS+ host IP address correctly configured in the router?

  • Is the identical TACACS+ host key entered on both the router and Cisco Secure ACS for Windows?

  • Is TACACS+ accounting configured on the router?

Troubleshooting Dial-In Client PC Problems

If the dial-in user is a Windows 95 or Windows 98 PC using DUN, here are some things to check:

  • Is the proper version of DUN installed? It should be DUN version 1.3.

  • Are connection properties configured to use Require Encrypted Password under Server Type?

  • Is the connection configured to use the correct protocol?

  • Is the selected Dial-Up Server type PPP: Windows 95/98, Windows NT 3.5, Internet?

  • Is the user authorized to use a specific command?

Other problems may be encountered with remote administration. Check the following:

  • Ensure that the web browser is correctly configured—enough cache is allocated and Java is enabled.

  • Ensure that Remote Administration is configured to allow remote web browser access (IP address and username/password).

Troubleshooting Using Cisco IOS Commands

The following Cisco IOS debug commands are useful for troubleshooting:

debug aaa authentication
debug aaa authorization
debug tacacs
debug radius
4. TACACS+ Overview | Next Section Previous Section

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