Guest WLAN Web Auth problem

Answered Question
Jun 7th, 2010
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Was just wondering whether anyone else had seen this problem as it is defeating TAC right now…

We have a number of 4402 WLCs on various sites and another one in a DMZ acting as an anchor controller for the guest network. We’re using just the basic web auth built into the WLC for access out on to the Internet for visiting third parties. All the EOIP stuff is setup and working and all clients can associate and get an IP address.

All clients get redirected to the authentication page and all clients appear to authenticate successfully. With the exception of a few clients, at this stage most get stuck and cannot browse the web; the pages just time out. All other Internet traffic (SSH, TELNET, SMTP, ICMP) works fine once authenticated , just not HTTP/HTTPS.

We have upgraded the WLCs to the latest code on the advice of TAC (6.0.196) but this made no difference. The problem seems to happen on all OSs (Mac, XP, Vista, Windows 7, Ubuntu, iPhone) and all browsers (IE6, IE7, IE8, Safari, Firefox, Chrome). We have tried upgrading drivers and changing browser settings, but nothing seems to help. We have working XP laptops and non-working XP latops; it just doesn’t make any sense.

The attached packet capture shows a non-working laptop and the only thing I noticed was very large window sizes (512k) which seems a bit odd.

Any ideas?

Thanks

Correct Answer by spirotsares about 7 years 1 week ago

We had the same problem. After discovering altering the MTU size on the client machine would allow browsing we changed the tcp mss adjust setting to 1300. The setting is under Wireless -> Radios -> Global configuration.  Default is 1363 when turned on but we had to use 1360 or less to work from all clients.  HTTP worked after that.


Hope this helps

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Correct Answer
spirotsares Fri, 06/18/2010 - 18:36
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We had the same problem. After discovering altering the MTU size on the client machine would allow browsing we changed the tcp mss adjust setting to 1300. The setting is under Wireless -> Radios -> Global configuration.  Default is 1363 when turned on but we had to use 1360 or less to work from all clients.  HTTP worked after that.


Hope this helps

gabriolinari Tue, 06/22/2010 - 15:50
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hi there


im having a bit of similar problem and it's driving me nuts. to sum it short. cisco router with web authentication as explained by the first post here. i have 2 laptops, one runs xp home and other one runs win 7 professional, both machines have pretty much the same stuff on.


the difference is that with the XP one wireless works great and never disconnects, with the win 7 machine instead, it disconnects me every 10-20 minutes or so, i came up with a trick that is to keep a streaming radio on the background, that way sometimes im connected also for 2-3-4 hours but looks like it times out again after an XX amount of time.


so should i change the MTU value on the win 7 machine to what? i just lowered it to 1440 from 1500 i had before but still disconnects and gets me the web authentication page. happens the very same with either firefox 3.6 and internet explorer 8.


help much apperciated, please answer here or to my mail gabrio81ATgmail.com


thanks

gabrio

gabriolinari Thu, 06/24/2010 - 13:50
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hi there


apparently i have a fix for the issue, it has just been tested for over 8 hours and my computer running wireless on windows 7 never disconected anymore (and i don't have either quick 1 second hangs anymore)....HOW????? it was the wireless driver!!


my computer has an Atheros 928x wireless card and i was running version 8.0.0... (can't remember the exact version) which as far as i know was the version bundled with the original installation alhough i dont remember if i had an update from somewhere else... anyway. i did this:


1. went to device manager, clicked on the wireless card, clicked delete, then confirm with the box about deletion of the software connected with the device.... then clicked on "scan for hardware changes" - in theory i wanted to update the driver with another .exe i downloaded but i thought let's give a go... and long story short, win 7 found in "his" files another suitable driver, probably the "generic" one, but nevertheless works as a charm, driver version is 2.0.0.74, driver date 09/06/2009, driver provider: microsoft, digital signer: microsoft windows, driver name : Atheros AR928X Wireless Network Adapter.


if you need more info about the driver let me know!


gabrio

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