This document explains how to use an external web server in order to
set up a wireless LAN controller (WLC) for web authentication.
Ensure that you meet these requirements before you attempt this
Basic knowledge of the configuration of Lightweight Access Points
(LAPs) and Cisco WLCs
Basic knowledge of Lightweight Access Point Protocol (LWAPP) and
Control and Provisioning of Wireless Access Points (CAPWAP)
Knowledge on how to set up and configure an external web server
Knowledge on how to set up and configure DHCP and DNS
The information in this document is based on these software and
Cisco 4400 WLC that runs firmware release 126.96.36.199
Cisco 1131AG Series LAP
Cisco 802.11a/b/g Wireless Client Adapter that runs firmware release
External web server that hosts the web authentication login
DNS and DHCP Servers for address resolution and IP address allocation
to wireless clients
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.
Technical Tips Conventions for more information on document
Web authentication is a Layer 3 security feature that causes the
controller to not allow IP traffic (except DHCP and DNS -related packets) from
a particular client until that client has correctly supplied a valid username
and password. Web Authentication is a simple authentication method without the
need for a supplicant or client utility.
Web authentication can be performed using:
Default login window on the WLC
Modified version of the default login window on the
A customized login window that you configure on an external web
server (External web authentication)
A customized login window that you download to the controller
This document provides a configuration example to explain how to
configure the WLC to use a login script from an external web server.
With external web authentication, the login page used for web
authentication is stored on an external web server. This is the sequence of
events when a wireless client tries to access a WLAN network which has external
web authentication enabled:
The client (end user) connects to the WLAN and opens a web browser
and enters a URL, such as www.cisco.com.
The client sends a DNS request to a DNS server in order to resolve
www.cisco.com to IP address.
The WLC forwards the request to the DNS server which, in turn,
resolves www.cisco.com to IP address and sends a DNS reply. The controller
forwards the reply to the client.
Client tries to initiate a TCP connection with the www.cisco.com IP
address by sending the TCP SYN packet to the www.cisco.com IP address.
The WLC has rules configured for the client and hence can act as a
proxy for www.cisco.com. It sends back a TCP SYN-ACK packet to the client with
source as the IP address of www.cisco.com. The client sends back a TCP ACK
packet in order to complete the three way TCP handshake and the TCP connection
is fully established.
The client sends an HTTP GET packet destined to www.google.com. The
WLC intercepts this packet, sends it for redirection handling. The HTTP
application gateway prepares a HTML body and sends it back as the reply to the
HTTP GET requested by the client. This HTML makes the client go to the default
webpage URL of the WLC, for example,
The client then starts the HTTPS connection to the redirect URL which
sends it to the 188.8.131.52. This is the virtual IP address of the controller. The
client has to validate the server certificate or ignore it in order to bring up
the SSL tunnel.
Because external web authentication is enabled, the WLC redirects the
client to the external web server.
The external web auth login URL is appended with parameters such as
the AP_Mac_Address, the client_url (www.cisco.com) and the action_URL that the
client needs to contact the controller web server.
Note: The action_URL tells the web server that the username and password
is stored on the controller. The credentials must be sent back to the
controller in order to get authenticated.
The external web server URL leads the user to a login page.
The login page takes user credentials input, and sends the request
back to the action_URL, example http://184.108.40.206/login.html, of the WLC web
The WLC web server submits the username and password for
The WLC initiates the RADIUS server request or uses the local
database on the WLC and authenticates the user.
If authentication is successful, the WLC web server either forwards
the user to the configured redirect URL or to the URL the client started with,
such as www.cisco.com.
If authentication fails, then the WLC web server redirects user back
to the customer login URL.
Note: In order to configure external webauthentication to use ports other
than HTTP and HTTPS, issue this command:
(Cisco Controller) >config network web-auth-port
<port> Configures an additional port to be redirected for web authentication.
The configuration example uses this setup. A LAP is registered to the
WLC. You need to configure a WLAN guest for the guest users
and have to enable web authentication for the users. You also need to ensure
that the controller redirects the user to the external web server URL (for
external web authentication). The external web server hosts the web login page
which is used for authentication.
The user credentials must be validated against the local database
maintained on the controller. After successful authentication, the users should
be allowed access to the WLAN guest. The controller and other devices need to
be configured for this setup.
Note: You can use a customized version of the login script, which will be
used for web authentication. You can download a sample Web Authentication
script from the Cisco Software
Downloads page. For example, for the 4400 controllers, navigate to
Products > Wireless > Wireless LAN Controller > Standalone
Controllers > Cisco 4400 Series Wireless LAN Controllers > Cisco 4404
Wireless LAN Controller > Software on Chassis > Wireless Lan Controller
Web Authentication Bundle-1.0.1 and download the
Note: The customized web auth bundle has a limit of up to 30 characters for
filenames. Ensure that no filenames within the bundle are greater than 30
Note: This document assumes that the DHCP, DNS and external web servers are
configured. Refer to the appropriate third party documentation for information
on how to configure the DHCP, DNS and external web server.
Before you configure the WLC for external web authentication, you must
configure the WLC for basic operation and register the LAPs to the WLC. This
document assumes that the WLC is configured for basic operation and that the
LAPs are registered to the WLC. Refer to
AP (LAP) Registration to a Wireless LAN Controller (WLC) if you are a
new user trying to set up the WLC for basic operation with LAPs.
Complete these steps in order to configure the LAPs and WLC for this
Create a Dynamic Interface for the Guest
Create a Preauthentication
Create a Local Database on the WLC for the Guest
Configure the WLC for External Web
Configure the WLAN for Guest
Complete these steps in order to create a dynamic interface for the
From the WLC GUI, choose Controllers >
The Interfaces window appears. This window lists the interfaces
that are configured on the controller. This includes the default interfaces,
which are the management interface, ap-manager interface, the virtual interface
and the service port interface, and the user defined dynamic
Click New in order to create a new dynamic
In the Interfaces > New window, enter the
Interface Name and the VLAN Id. Then, click
In this example, the dynamic interface is named
guest and the VLAN Id is assigned
In the Interfaces > Edit window, for the
dynamic interface, enter the IP address, the subnet mask, and the default
gateway. Assign it to a physical port on the WLC, and enter the IP address of
the DHCP server. Then, click
When using an external web server for web authentication, some of the
WLC platforms need a pre-authentication ACL for the external web server (the
Cisco 5500 Series Controller, a Cisco 2100 Series Controller ,Cisco 2000 series
and the controller network module). For the other WLC platforms the
pre-authentication ACL is not mandatory.
However, it is a good practice to configure a preauthentication ACL for
the external web server when using external web authentication.
Complete these steps in order to configure the preauthentication ACL
for the WLAN:
From the WLC GUI, choose Security > Access Control
This window allows you to view current ACLs that are similar to
standard firewall ACLs.
Click New in order to create a new
Enter the name of the ACL and click
In this example, the ACL is named
For the new ACL created, click
The ACL > Edit window appears. This window lets the user define
new rules or modify rules of the ACL that exist.
Click Add New Rule.
Define an ACL rule which allows access for the clients to the
external web server.
In this example, 172.16.1.92 is the external web server IP
Click Apply in order to commit the
The user database for the guest users can either be stored on the
Wireless LAN Controller's local database, or might be stored external of the
In this document the local database on the controller is used to
authenticate users. You must create a Local Net User and define a password for
the web authentication client login. Complete these steps in order to create
the user database on the WLC:
From the WLC GUI, choose
Click Local Net Users from the AAA menu on the
Click New in order to create a new
A new window displays that asks for username and password
Enter a User Name and Password in order to create a new user, then
confirm the password that you want to use.
This example creates the user named User1.
Add a description, if you choose.
This example uses Guest User1.
Click Apply in order to save the new user
Repeat steps 3-6 to add more users to the database.
The next step is to configure the WLC for the external web
authentication. Complete these steps:
From the controller GUI, choose Security > Web Auth >
Web Login Page in order to access the Web Login
From the Web Authentication Type drop-down box, choose
External (Redirect to external server).
In the External Web server section, add the new
external web server.
In the Redirect URL after login field, enter the
URL of the page to which the end user will be redirected to upon successful
authentication. In the External Web Auth URL field, enter the
URL where the login page is stored on the external web server.
Note: In WLC versions 5.0 and later, the logout page for
web-authentication can also be customized. Refer to the
Login , Login failure and Logout pages per WLAN section of the
Wireless LAN Controller Configuration Guide,5.2 for more
information on how to configure it.
The final step is to create WLANs for the guest users. Complete these
Click WLANs from the controller GUI in order to
create a WLAN.
The WLANs window appears. This window lists the WLANs configured on
Click New in order to configure a new
In this example, the WLAN is named Guest and the
WLAN ID is 1.
In the WLAN > Edit window, define the parameters specific to the
For the guest WLAN, in the General tab, choose the appropriate
interface from the Interface Name field.
This example maps the dynamic interface guest
that was previously created to the WLAN guest.
Go to the Security tab. Under Layer 2 Security,
None is selected in this example.
Note: Web authentication is not supported with 802.1x authentication.
This means you cannot choose 802.1x or a WPA/WPA2 with 802.1x as the Layer 2
security when you use web authentication.Web authentication is supported with
all other Layer 2 security parameters.
In the Layer 3 Security field, check the Web
Policy check box and choose the Authentication
This option is chosen because web authentication is used to
authenticate the wireless guest clients.
Choose the appropriate Preauthentication ACL from the drop-down
In this example, the preauthentication ACL that was created
previously is used.
The wireless client comes up and the user enters the URL, such as
www.cisco.com, in the web browser. Because the user has not been authenticated,
the WLC redirects the user to the external web login URL.
The user is prompted for the user credentials. Once the user submits
the username and password, the login page takes user credentials input and on
submit sends the request back to the action_URL example,
http://220.127.116.11/login.html, of the WLC web server. This is provided as an input
parameter to the customer redirect URL, where 18.104.22.168 is the Virtual Interface
Address on the switch.
The WLC authenticates the user against the local database configured on
the WLC. After successful authentication, the WLC web server either forwards
the user to the configured redirect URL or to the URL the client started with,
such as www.cisco.com.
Use these debug commands in order to troubleshoot your configuration.
debug mac addr <client-MAC-address
debug aaa all enable
debug pem state enable
debug pem events enable
debug dhcp message enable
debug dhcp packet enable
debug pm ssh-appgw enable
debug pm ssh-tcp enable
Use this section to troubleshoot your configuration.
Problem: When clients are redirected to Cisco's
external web authentication server, they receive a certificate warning. There
is a valid certificate on the server, and if you connect to the external web
authentication server directly the certificate warning is not received. Is this
because the virtual IP address (22.214.171.124) of the WLC is presented to the client
instead of the actual IP address of the external web authentication server that
is associated with the certificate?
Solution: Yes. Whether or not you perform local or
external web authentication, you still hit the internal web server on the
controller. When you redirect to an external web server, you still receive the
certificate warning from the controller unless you have a valid certificate on
the controller itself. If the redirect is sent to https, you receive the
certificate warning from the controller and from the external web server,
unless both have a valid certificate.
In order to get rid of the certificate warnings all together, you need
to have a root level certificate issued and downloaded onto your controller.
The certificate is issued for a host name and you put that host name in the DNS
host name box under the virtual interface on the controller. You also need to
add the host name to your local DNS server and point it to the virtual IP
address (126.96.36.199) of the WLC.
Signing Request (CSR) Generation for a Third-Party Certificate on a WLAN
Controller (WLC) for more information.
Problem: After the controller is upgraded to
188.8.131.52, the "page cannot be displayed " error message appears when you use a
downloaded web page for web authentication. This worked well prior to the
upgrade. The default internal web page loads without any problem .
Solution: From the WLC version 4.2 and later a new
feature is introduced wherein you can have multiple cutomized login pages for
In order to have the web page load properly, it is not sufficient to
set the web-authentication type as customized globally in the
Security > Web Auth > Web login page. It must also be
configured on a particular WLAN . In order to do this, complete these
Log into the GUI of the WLC.
Click on the WLANs tab, and access the profile of
the WLAN configured for Web-authentication.
On the WLAN > Edit page, click the Security
tab. Then, choose Layer 3.
On this page, choose None as the Layer 3
Check the Web Policy box, and choose the
Check the Over-ride Global Config Enable box,
choose Customized (Downloaded) as the Web Auth Type, and
select the desired login page from the Login Pagepull down
menu. Click Apply.