This document describes how to configure secure wireless access using
Wireless LAN Controllers (WLCs), Microsoft Windows 2003 software and Cisco
Secure Access Control Server (ACS) 4.0 via Extensible Authentication
Protocol-Transport Layer Security (EAP-TLS).
There is an assumption that the installer has knowledge of basic
Windows 2003 installation and Cisco controller installation as this document
only covers the specific configurations to facilitate the tests.
Before you begin, install the Windows Server 2003 with Service Pack
(SP)1 operating system on each of the servers in the test lab and update all
Service Packs. Install the controllers and APs and ensure that the latest
software updates are configured.
Important: At the time this document was written, SP1
is the latest Windows Server 2003 update, and SP2 with update patches is the
latest software for Windows XP Professional.
Windows Server 2003 with SP1, Enterprise Edition, is used so that
auto-enrollment of user and workstation certificates for EAP-TLS authentication
can be configured. This is described in the EAP-TLS
Authentication section of this document. Certificate auto-enrollment and
auto-renewal make it easier to deploy certificates and improve security by
automatically expiring and renewing certificates.
The primary purpose of this document is to provide you the step-by-step
procedure to implement the EAP-TLS under Unified Wireless Networks with ACS 4.0
and the Windows 2003 Enterprise server. The main emphasis is on auto-enrollment
of the client so that the client auto-enrolls and takes the certificate from
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
Open the Active Directory Domains and Trusts snap-in from the
Administrative Tools folder(Start > Administrative
Tools > Active Directory Domains and Trusts), and then right-click
the domain computer DC_CA.wirelessdemo.local.
Click Raise Domain Functional Level, and then
select Windows Server 2003 on the Raise Domain Functional
Install Dynamic Host Configuration Protocol (DHCP) as a Networking
Service component by using Add or Remove Programs in the
Open the DHCP snap-in from the Administrative Tools folder
(Start > Programs > Administrative Tools > DHCP, and
then highlight the DHCP server, DC_CA.wirelessdemo.local.
Click Action, and then click
Authorize in order to authorize the DHCP service.
On the console tree, right-click
DC_CA.wirelessdemo.local, and then click New
On the Welcome page of the New Scope wizard, click
On the Scope Name page, type CorpNet in the Name
Click Next and fill in these parameters:
Start IP address—172.16.100.1
End IP address—172.16.100.254
Click Next and enter 172.16.100.1
for the Start IP address and 172.16.100.100 for the End IP
address to be excluded. Then click Next. This reserves the IP
addresses in the range from 172.16.100.1 to 172.16.100.100. These reserved IP
addresses are not allotted by the DHCP server.
On the Lease Duration page, click Next.
On the Configure DHCP Options page, choose Yes, I want to
configure these options now and click Next.
On the Router (Default Gateway) page add the default router address
of 172.16.100.1 and click Next.
On the Domain Name and DNS Servers page, type
wirelessdemo.local in the Parent domain field, type
172.16.100.26 in the IP address field, and then click
Add and click Next.
On the WINS Servers page, click Next.
On the Activate Scope page, choose Yes, I want to activate
this scope now and click Next.
On the Completing the New Scope Wizard page, click
Note: IIS must be installed before you install Certificate Services and the
user should be part of the Enterprise Admin OU.
In the Control Panel, open Add or Remove Programs,
and then click Add/Remove Windows Components.
On the Windows Components Wizard page, choose Certificate
Services, and then click Next.
On the CA Type page, choose Enterprise root CA and
On the CA Identifying information page, type
wirelessdemoca in the Common name for this CA box. You can
enter the other optional details and then click Next. Accept
the defaults on the Certificate Database Settings page.
Click Next. Upon completion of the installation,
Click OK after you read the warning about
In the Active Directory Users and Computers console tree, click the
Computers folder and right-click on the computer for which you
want to assign wireless access. This example shows the procedure with computer
CLIENT which you added in step 7.
In the details pane of Active Directory Users and Computers,
double-click on the Group WirelessUsers.
Go to the Members tab and click Add.
In the Select Users, Contacts, Computers, or Groups dialog box,
type the name of the users that you want to add to the group. This example
shows how to add the user wirelessuser to the group. Click
In the Multiple Names Found dialog box, click OK.
The WirelessUser user account is added to the WirelessUsers group.
Click OK in order to save changes to the
Repeat this procedure to add more users to the
Cisco Secure ACS is a computer that runs Windows Server 2003 with SP1,
Standard Edition, that provides RADIUS authentication and authorization for the
controller. Complete the procedures in this section in order to configure ACS
as a RADIUS server:
Using a Domain Administrator account, login to the computer named
ACS to Cisco Secure ACS.
Note: Only installations performed at the computer where you install
Cisco Secure ACS are supported. Remote installations performed using Windows
Terminal Services or products such as Virtual Network Computing (VNC), are not
tested, and are not supported.
Insert the Cisco Secure ACS CD into a CD-ROM drive on the computer.
If the CD-ROM drive supports the Windows autorun feature, the Cisco
Secure ACS for Windows Server dialog box appears.
Note: If the computer does not have a required service pack installed,
a dialog box appears. Windows service packs can be applied either before or
after you install Cisco Secure ACS. You can continue with the installation, but
the required service pack must be applied after the installation is complete.
Otherwise, Cisco Secure ACS might not function reliably.
Perform one of these tasks:
If the Cisco Secure ACS for Windows Server dialog box appears,
If the Cisco Secure ACS for Windows Server dialog box does not
appear, run setup.exe, located in the root directory of the
Cisco Secure ACS CD.
The Cisco Secure ACS Setup dialog box displays the software license
Read the software license agreement. If you accept the software
license agreement, click Accept.
The Welcome dialog box displays basic information about the setup
After you have read the information in the Welcome dialog box,
The Before You Begin dialog box lists items that you must complete
before you continue with the installation. If you have completed all items
listed in the Before You Begin dialog box, check the corresponding box for each
item and click Next.
Note: If you have not completed all items listed in the Before You
Begin box, click Cancel and then click Exit
Setup. After you complete all items listed in the Before You Begin
dialog box, restart the installation.
The Choose Destination Location dialog box appears. Under
Destination Folder, the installation location appears. This is the drive and
path where the setup program installs Cisco Secure ACS.
If you want to change the installation location, complete these
Click Browse. The Choose Folder dialog box
appears. The Path box contains the installation location.
Change the installation location. You can either type the new
location in the Path box or use the Drives and Directories lists to select a
new drive and directory. The installation location must be on a drive local to
Note: Do not specify a path that contains a percent character, "%".
If you do so, the installation might appear to continue properly but fails
before it completes.
Note: If you specified a folder that does not exist, the setup
program displays a dialog box to confirm the creation of the folder. In order
to continue, click Yes.
In the Choose Destination Location dialog box, the new installation
location appears under Destination Folder.
The Authentication Database Configuration dialog box lists options
for authenticating users. You can authenticate with the Cisco Secure user
database only, or also with a Windows user database.
Note: After you install Cisco Secure ACS, you can configure
authentication support for all external user database types in addition to
Windows user databases.
If you want to authenticate users with the Cisco Secure user
database only, choose the Check the Cisco Secure ACS database
If you want to authenticate users with a Windows Security Access
Manager (SAM) user database or Active Directory user database in addition to
the Cisco Secure user database, complete these steps:
Choose the Also check the Windows User Database
The Yes, refer to "Grant dialin permission to user"
setting check-box becomes available.
Note: The Yes, refer to "Grant dialin permission to
user" setting check-box applies to all forms of access controlled by
Cisco Secure ACS, not just dial-in access. For example, a user accessing the
network through a VPN tunnel is not dialing into a network access server.
However, if the Yes, refer to "Grant dialin permission to
user" setting box is checked, Cisco Secure ACS applies the Windows
user dial-in permissions in order to determine whether to grant the user access
to the network.
If you want to allow access to users who are authenticated by a
Windows domain user database only when they have dial-in permission in their
Windows account, check the Yes, refer to "Grant dialin permission to
user" setting box.
The setup program installs Cisco Secure ACS and updates the Windows
Note: The listed features appear in the Cisco Secure ACS HTML interface
only if you enable them. After installation, you can enable or disable them on
the Advanced Options page in the Interface Configuration section.
For each feature you want to enable, check the corresponding box.
The Active Service Monitoring dialog box appears.
Note: After installation, you can configure active service monitoring
features on the Active Service Management page in the System Configuration
If you want Cisco Secure ACS to monitor user authentication
services, check the Enable Login Monitoring box. From the
Script to Execute list, choose the option you want applied in the event of an
authentication service failure:
No Remedial Action—Cisco Secure ACS does not run
Note: This option is useful if you enable event mail notifications.
Reboot—Cisco Secure ACS runs a script that
reboots the computer that runs Cisco Secure ACS.
Restart All—Cisco Secure ACS restarts all Cisco
Secure ACS services.
Restart RADIUS/TACACS+—Cisco Secure ACS restarts
only the RADIUS and TACACS+ services.
If you want Cisco Secure ACS to send an e-mail message when service
monitoring detects an event, check the Mail Notification box.
The Database Encryption Password dialog box appears.
Note: The Database Encryption Password is encrypted and stored in the
ACS registry. You might need to reuse this password when critical problems
arise and the database needs to be accessed manually. Keep this password at
hand so that Technical Support can gain access to the database. The password
can be changed each expiration period.
Enter a password for database encryption. The password needs to be
at least eight characters long and needs to contain both characters and digits.
There are no invalid characters. Click Next.
The setup program finishes and the Cisco Secure ACS Service
Initiation dialog box appears.
For each Cisco Secure ACS Services Initiation option you want,
check the corresponding box. The actions associated with the options occur
after the setup program finishes.
Yes, I want to start the Cisco Secure ACS Service
now—Starts the Windows services that compose Cisco Secure ACS. If you
do not select this option, the Cisco Secure ACS HTML interface is not available
unless you reboot the computer or start the CSAdmin service.
Yes, I want Setup to launch the Cisco Secure ACS
Administrator from my browser following installation—Opens the Cisco
Secure ACS HTML interface in the default web browser for the current Windows
Yes, I want to view the Readme File—Opens the
README.TXT file in Windows Notepad.
If you selected an option, the Cisco Secure ACS services start. The
Setup Complete dialog box displays information about the Cisco Secure ACS HTML
Note: The rest of the configuration is documented under the section for
the EAP type that is configured.
Note: The assumption is that the controller has basic connectivity to the
network and IP reachability to the management interface is successful.
Login into the controller by browsing to
Login with the default user admin and default
Create the Interface VLAN mapping under the Controller menu.
In the Interface name field type Employee. (This
field can be any value you like.)
In the VLAN ID field type 20. (This field can be
any VLAN that is carried in the network.)
Configure the information as this Interfaces > Edit window
In the WLAN SSID field type Employee.
Configure the information as this WLANs > Edit window
Note: WPA2 is the chosen Layer 2 encryption method for this lab. In
order to allow WPA with TKIP-MIC clients to associate to this SSID, you can
also check the boxes WPA compatibility mode and Allow
WPA2 TKIP Clients or those clients that do not support the the 802.11i
AES encryption method.
Click the Security menu and add the RADIUS
Add the RADIUS server IP address (172.16.100.25) which is the ACS
server configured earlier.
Ensure that the shared key matches the AAA client configured in the
The basic configuration is now complete and you can begin to test
EAP-TLS authentication requires computer and user certificates on the
wireless client, the addition of EAP-TLS as an EAP type to the remote access
policy for wireless access, and a reconfiguration of the wireless network
In order to configure DC_CA to provide auto-enrollment for computer and
user certificates, complete the procedures in this section.
Note: Microsoft has changed the Web Server template with the release of the
Windows 2003 Enterprise CA so that keys are no longer exportable and the option
is greyed out. There are no other certificate templates supplied with
certificate services that are for server authentication and give the ability to
mark keys as exportable that are available in the drop-down so you have to
create a new template that does so.
Note: Windows 2000 allows for exportable keys and these procedures do not
need to be followed if you use Windows 2000.
In the Details pane of the Certificate Templates snap-in, click the
Web Server template.
On the Action menu, click Duplicate Template.
In the Template display name field, type
Go to the Request Handling tab and check Allow private key
to be exported.
Choose Requests must use one of the following CSPs
and check Microsoft Base Cryptographic Provider v1.0. Uncheck
any other CSPs that are checked and then click OK.
Go to the Subject Name tab, choose Supply in the
request and click OK.
Go to the Security tab, highlight the Domain Admins
Group and ensure that the Enroll option is checked
Important: If you choose to build from this Active
Directory information only, check User principal name (UPN)
and uncheck Include email name in Subject name and E-mail name
because an e-mail name was not entered for the WirelessUser account in the
Active Directory Users and Computers snap-in. If you do not disable these two
options, auto-enrollment attempts to use e-mail, which results in an
There are additional security measures if needed to prevent
certificates from being automatically pushed out. These can be found under the
Issuance Requirements tab. This is not discussed further in this document.
Click OK to save the template and move onto
issuing this template from the Certificate Authority snap-in.
Important: The ACS server must obtain a server
certificate from the Enterprise root CA server in order to authenticate a WLAN
Important: Ensure that the IIS Manager is not open
during the certificate setup process as it causes problems with cached
Log into the ACS server with an account that has Enterprise Admin
On the local ACS machine, point the browser at the Microsoft
certification authority server at
http://IP-address-of-Root-CA/certsrv. In this case, the IP
address is 172.16.100.26.
Log in as the Administrator.
Choose Request a Certificate and click
Choose Advanced Request and click
Choose Create and submit a request to this CA and
Important: The reason for this step is due to the
fact that Windows 2003 does not allow for exportable keys and you need to
generate a certificate request based on the ACS Certificate that you created
earlier that does.
From the Certificate Templates, select the certificate template
created earlier named ACS. The options change after you select
Configure the Name to be the fully qualified domain name of the ACS
server. In this case the ACS server name is cisco_w2003.wirelessdemo.local.
Ensure that Store certificate in the local computer certificate
store is checked and click Submit.
A pop up window appears that warns about a potential scripting
violation. Click Yes.
Click Install this certificate.
A pop up window appears again and warns about a potential scripting
violation. Click Yes.
After you click Yes, the certificate is installed.
At this point, the certificate is installed in the Certificates
folder. In order to access this folder, choose Start > Run,
type mmc, press Enter, and choose
Personal > Certificates.
Now that the certificate is installed to the local computer (ACS or
cisco_w2003 in this example), you need to generate a certificate file (.cer)
for the ACS 4.0 certificate file configuration.
On the ACS server (cisco_w2003 in this example), point the browser
at the Microsoft Certification Authority server to http://172.16.100.26
CLIENT is a computer that runs Windows XP Professional with SP2 that
acts as a wireless client and obtains access to Intranet resources through the
wireless AP. Complete the procedures in this section in order to configure
CLIENT as a wireless client.
Log off and then log on by using the WirelessUser account in the
Note: Update computer and user configuration group policy settings and
obtain a computer and user certificate for the wireless client computer
immediately, by typing gpupdate at a command prompt.
Otherwise, when you log off and then log on, it performs the same function as
gpupdate. You must be logged on to the domain by connecting
over the wire.
Note: In order to validate that the certificate is automatically
installed on the client, open the certificate MMC and validate that the
WirelessUser certificate is available in the Personal Certificates folder.
Choose Start > Control Panel, double-click
Network Connections, and then right-click Wireless
Click Properties, go to the Wireless Networks tab,
and ensure that User Windows to configure my wireless network
settings is checked.
Go to the Association tab, and type Employee in
the Network name (SSID) field.
Ensure that Data Encryption is set to WEP and
The key is provided for me automatically is checked.
Go to the Authentication tab.
Validate that EAP type is configured to use Smart Card or
other Certificate. If it is not, select it from the drop-down menu.
If you want the machine to be authenticated prior to login (which
allows login scripts or group policy pushes to be applied) choose the option
Authenticate as computer when computer information is
Ensure that the boxes in this window are checked.
Click OK three times.
Right-click the wireless network connection icon in systray and
then click View Available Wireless Networks.
Click the Employee wireless network and click
These screen shots indicate if the connection completes
After the authentication is successful, check the TCP/IP
configuration for the wireless adapter by using Network Connections. It should
have an address range of 172.16.100.100-172.16.100.254 from the DHCP scope or
the scope created for the wireless clients.
In order to test functionality, open up a browser and browse to
http://wirelessdemoca (or the IP address of the Enterprise CA