03-05-2014 10:04 AM - edited 07-05-2021 12:20 AM
hi All,
I have configured my WLC as DHCP server. So in this case do i need to enable dhcp option 82 on the dynamic interface.
I have a guest vlan, i have dynamic interface for this and user id's created for it, but users are stuck in WEbauth_reqd. i am unable to understand whats the issue.Anyone for help
03-05-2014 10:09 AM
HI,
DHCP option 82 enables the controller to act as a DHCP relay agent to prevent DHCP client requests from untrusted sources. You can configure the controller to add option 82 information to DHCP requests from clients before forwarding the requests to the DHCP server.
I think you need to enter controller ip address as DHCP server on dynamic interface of WLC.
Regards
03-05-2014 10:22 AM
Hi Royce,
Just FYI, here is what should happen during webauth.
1) Client associates.
2) WLC moves client into DHCP_REQD Policy Manager state.
3) Client either does DHCP or WLC learns the client's IP address.
4) WLC moves client into WEBAUTH_REQD Policy Manager state.
5) Client opens browser.
6) Client sends DNS lookup for the default web page.
7) DNS responds with IP address.
8) Browser sends TCP SYN to IP address.
9) WLC intercepts TCP SYN and continues TCP handshake.
10) Browser sends HTTP GET with requested URL.
11*) WLC sends HTTP redirect to https://
12*) Client opens https://
03-06-2014 12:23 AM
Steps 1 -4 goes smooth i beleive, but i dont have any direct interaction with the customer local site so donet know whether they are doing it correctly.
In WLC virtual interface i have put a domain.com so guest wont see page with virtual rather with this domain.com/login
So once customer completes 1 to 4, shall i ask customer to open browser and type google.com and see whether it works (means at this point it should get a response from WLC with internal default authentication type)
03-05-2014 07:12 PM
Hi,
If the clients are in webauth req state then its not an issue with the DHCP.
Clients move to webauth req state once they get the IP Address.
Without an IP address the wireless client can not reach the webauth req state.
Are you using layer 3 security on the WLAN.
What type of webauth you are using : Internal , Customized, External.
What is the IP address of the Virtual interface.
Is it an Anchor - Foreign setup.
Where is the DHCP configured for the Wireless clients connecting on this WLAN.
Thanks and regards,
Manas Pratap Singh.
03-06-2014 01:09 AM
If the clients are in webauth req state then its not an issue with the DHCP.
Clients move to webauth req state once they get the IP Address.
Without an IP address the wireless client can not reach the webauth req state - Success as i can see client got an IP from DHCP(WLC)
Are you using layer 3 security on the WLAN. - Yes Web Auth
What type of webauth you are using : Internal , Customized, External. - Internal
What is the IP address of the Virtual interface - 1.1.1.1
No Anchor foreign setup
Where is the DHCP configured for the Wireless clients connecting on this WLAN - DHCP configured on WLC
03-06-2014 05:09 AM
I don't know what you have configured thus far, but just a few thing I want to point out and make sure you have done properly..
Make sure you have dhcp proxy enabled on the WLC. Also the interface that your putting the guest users on, you need to configure the wlc management ip as the primary dhcp address.
Thanks,
Scott
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03-06-2014 08:59 AM
Yeah Scott i have configured it the same, but when i check the association i see "Webauth_reqd" state in Policy manager. Not sure whether they are providing some wrong user id or not
03-06-2014 12:14 PM
You would actually have to see it for yourself... users are users and maybe they are.... you can enable client exclusion and see if they get excluded and that would tell you that they are not typing it right.
Thanks,
Scott
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03-06-2014 05:37 PM
Hi,
Thanks for the reply.
Please try to put the following url in a browser of the wireless client.
If by using this url you are getting the login page then the issue should be at the dns side.
If we are not getting the login page using this url then the issue should be at the WLC side.
Webauth cases need a detailed troubleshooting and we should proceed step by step.
Thanks and regards,
Manas Pratap Singh.
03-05-2014 10:09 PM
we can configure option 82 to prevent DHCP client requests from untrusted sources that is the main function of it but make sure you follow the following steps for trouble shooting
After you configure web authentication, if the feature does not work as expected, complete these troubleshooting steps:
Check if the client gets an IP address. If not, users can uncheck DHCP Required on the WLAN and give the wireless client a static IP address. This assumes association with the access point. Refer to the IP addressing issues section of Troubleshooting Client Issues in the Cisco Unified Wireless Network for troubleshooting DHCP related issues.
On WLC versions earlier than 3.2.150.10, you must manually enter https://1.1.1.1/login.html in order to navigate to the web authentication window.
The next step in the process is DNS resolution of the URL in the web browser. When a WLAN client connects to a WLAN configured for web authentication, the client obtains an IP address from the DHCP server. The user opens a web browser and enters a website address. The client then performs the DNS resolution to obtain the IP address of the website. Now, when the client tries to reach the website, the WLC intercepts the HTTP Get session of the client and redirects the user to the web authentication login page.
Therefore, ensure that the client is able to perform DNS resolution for the redirection to work. On Windows, choose Start > Run, enter CMD in order to open a command window, and do a “nslookup www.cisco.com" and see if the IP address comes back.
On Macs/Linux: open a terminal window and do a “nslookup www.cisco.com" and see if the IP address comes back.
If you believe the client is not getting DNS resolution, you can either:
Enter either the IP address of the URL (for example, http://www.cisco.com is http://198.133.219.25)
Try to directly reach the controller's webauth page with https://
Does entering this URL bring up the web page? If yes, it is most likely a DNS problem. It might also be a certificate problem. The controller, by default, uses a self-signed certificate and most web browsers warn against using them.
For web authentication using customized web page, ensure that the HTML code for the customized web page is appropriate.
You can download a sample Web Authentication script from Cisco Software Downloads. For example, for the 4400 controllers, choose 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 webauth_bundle.zip file.
These parameters are added to the URL when the user's Internet browser is redirected to the customized login page:
ap_mac—The MAC address of the access point to which the wireless user is associated.
switch_url—The URL of the controller to which the user credentials should be posted.
redirect—The URL to which the user is redirected after authentication is successful.
statusCode—The status code returned from the controller's web authentication server.
wlan—The WLAN SSID to which the wireless user is associated.
These are the available status codes:
Status Code 1: "You are already logged in. No further action is required on your part."
Status Code 2: "You are not configured to authenticate against web portal. No further action is required on your part."
Status Code 3: "The username specified cannot be used at this time. Perhaps the username is already logged into the system?"
Status Code 4: "You have been excluded."
Status Code 5: "The User Name and Password combination you have entered is invalid. Please try again."
All the files and pictures that need to appear on the Customized web page should be bundled into a .tar file before uploading to the WLC. Ensure that one of the files included in the tar bundle is login.html. You receive this error message if you do not include the login.html file:
Refer to the Guidelines for Customized Web Authentication section of Wireless LAN Controller Web Authentication Configuration Example for more information on how to create a customized web authentication window.
Note: Files that are large and files that have long names will result in an extraction error. It is recommended that pictures are in .jpg format.
Internet Explorer 6.0 SP1 or later is the browser recommended for the use of web authentication. Other browsers may or may not work.
Ensure that the Scripting option is not blocked on the client browser as the customized web page on the WLC is basically an HTML script. On IE 6.0, this is disabled by default for security purposes.
Note: The Pop Up blocker needs to be disabled on the browser if you have configured any Pop Up messages for the user.
Note: If you browse to an https site, redirection does not work. Refer to Cisco bug ID CSCar04580 (registered customers only) for more information.
If you have a host name configured for the virtual interface of the WLC, make sure that the DNS resolution is available for the host name of the virtual interface.
Note: Navigate to the Controller > Interfaces menu from the WLC GUI in order to assign a DNS hostname to the virtual interface.
Sometimes the firewall installed on the client computer blocks the web authentication login page. Disable the firewall before you try to access the login page. The firewall can be enabled again once the web authentication is completed.
Topology/solution firewall can be placed between the client and web-auth server, which depends on the network. As for each network design/solution implemented, the end user should make sure these ports are allowed on the network firewall.
Protocol | Port |
---|---|
HTTP/HTTPS Traffic | TCP port 80/443 |
CAPWAP Data/Control Traffic | UDP port 5247/5246 |
LWAPP Data/Control Traffic (before rel 5.0) | UDP port 12222/12223 |
EOIP packets | IP protocol 97 |
Mobility | UDP port 16666 (non secured) UDP port 16667 (secured IPSEC tunnel) |
For web authentication to occur, the client should first associate to the appropriate WLAN on the WLC. Navigate to the Monitor > Clients menu on the WLC GUI in order to see if the client is associated to the WLC. Check if the client has a valid IP address.
Disable the Proxy Settings on the client browser until web authentication is completed.
The default web authentication method is PAP. Ensure that PAP authentication is allowed on the RADIUS server for this to work. In order to check the status of client authentication, check the debugs and log messages from the RADIUS server. You can use the debug aaa all command on the WLC to view the debugs from the RADIUS server.
Update the hardware driver on the computer to the latest code from manufacturer's website.
Verify settings in the supplicant (program on laptop).
When you use the Windows Zero Config supplicant built into Windows:
Verify user has latest patches installed.
Run debugs on supplicant.
On the client, turn on the EAPOL (WPA+WPA2) and RASTLS logs from a command window, Start > Run > CMD:
netsh ras set tracing eapol enable netsh ras set tracing rastls enable
In order to disable the logs, run the same command but replace enable with disable. For XP, all logs will be located in C:\Windows\tracing.
If you still have no login web page, collect and analyze this output from a single client:
debug clientdebug dhcp message enable debug aaa all enable debug dot1x aaa enable debug mobility handoff enable
03-06-2014 06:59 PM
Hi
You do not want to enable DHCP option 82 to get this working.
DHCP option 82 is required only if you want to get client attachement details (like which AP they connect to) & below post should able to help you understand this feature.
1. http://mrncciew.com/2013/05/18/understanding-dhcp-option-82/
2. http://mrncciew.com/2013/06/08/wlc-dhcp-option-82-config-example/
HTH
Rasika
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03-07-2014 06:49 AM
It doesn't seem to be DHCP option 82 issue but related to web auth.
Is there too much load on WLC.. does this happen only in high load condition when lot many clients are already connected?
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