Accesspoints and PDA's

[Phoenix]

hey guys, I have a nice case again...

Required:

Wireless AP

Laptop

PDA (Windows mobile 5)

USB cable for pda

active sync.

Access point installed with WPA and TKIP.

Laptop associated with AP.

Works fine.

PDA works fine too

Now i want to sync.

My usb cable goes into the laptop usb port and in the PDA.

On active sync the wireless connection drops for everyone associated with that AP loses his wireless connection.

This happens on a cisco aironet 1240AG wireless AP, but also on lower AP's as a Linksys..

1 difference, the IOS of a cisco AP can restore, the linksys just hangs on this cause..

Using WPA with AES it works fine. same thing with WEP encryption..

now that we intend to use AES its not a problem, but I just want to know the cause of this strange behaviour..

Oh yea, the logfile shows:

1 Warning TKIP michael MIC failure was detected on a packet (TSC=0xD2) recieved from /mac-address/

2 Warning TKIP michael MIC failure was detected on a packet (TSC=0xD2) recieved from /same mac-address as first line mac/

3 Error TKIP michael MIC failures were detected within 0 seconds on Dot11radio0 interface. The interface will be put on MIC  failure hold stat for next 60 seconds.

I tried the "countermeasure tkip hold-time 0" command to change the hold time to 0.

Now trying again, only the connection of the person connecting the PDA drops, but the logfile gets 5 messages of "Warning TKIP michael MIC failure was detected on a packet (TSC=0xD2) recieved from /mac-address/" every second...

dunno but i just dont want to wait the log buffer getting filled.

has anyone a clue what this could be?

[gryphon]

I doubt besides you and me any one here knows Cisco Aeronets ;)

Small sidemark, when you connect the PDA to the laptop, your PDA can be reached router via your laptop and by it's own WLAN adapter. So the AP get's the same machines on 2 different paths in it's WLAN. Don't know it that is really happening, just a first guess.

Something like when you put a load-balanced Windows server with 2 NIC's on a non-trunked switch. Grap a cup of hot coco and waith untill the switch stops switching.

[Phoenix]

That was my first guess too indeed.. but its not..

I searched the big-o-net and found this:

Since Windows Mobile 5.0 and ActiveSync 4.0 now utilize the Windows sytem TCP/IP stack for communication, the device will appear as a network interface and can be interrupted by a Network Connection Manager utility. Some utilities may mistake the ActiveSync connection as a valid internet connection and shut it down in favor of a Wireless LAN connection[2].

and for what I noticed today is that TKIP has to be the one causing all this... AES, WEP and no encryption works fine.

I grap a cup of hot chocolate and wait untill Microsoft makes another great move...

[veK]

I doubt besides you and me any one here known Cisco Aeronets ;)

I know too...

but unfortunately  I can't help with the problem, I'm not into pda stuff that much  :-

[erjin999]

I have a vague inkling :P I mean I know !