Cisco Aironet 1100 Encryption problem

Posted on 2005-05-11
Last Modified: 2010-05-18
I have a client that has 4 Cisco Aironet 1100 APs installed with about 50 clients.  All clients can connect with no security.  When we try to add WEP encryption, none of the clients can connect.  They can see the access point but can't connect.  Any ideas on how to resolve this?
Question by:071171
    LVL 11

    Expert Comment

    What authentication type(s) do you have enabled?  Without WEP it should probably be "open", with WEP it pretty much needs to be "shared".


    Author Comment

    We have WEP enabled with Shared authentication. We set 128 bit encryption, and when that didn't work, we tried 40 bit and still nothing.
    LVL 1

    Expert Comment

    Pretty muppetty comment, and I apologise in advance.   But have you set up the keys etc on the client PC's ????Been a while since i worked on the Aironet kit, but I seem to remember there was a tick box somewhere that needed unchecking when setting up the WEP you get any error messages on the clients when you try to connect ?  Can you see the MAC addresses on the Aironet ??????

    Author Comment

    jajjones -

    The clients can see the AP; they just can seem to connect.  We have added just 1 key to begin with to test.  The clients say the typical "limited or no connection".  They are recognized by the AP as clients connecting for access. Something I failed to mention before: the client has 5 identical Cisco 1100's that were installed.  All have the same SSID.  The internal IT guy decided to add the security to just 1 of the 5 to test so we wouldn't take everyone of the Internet at once.  Is it possible that just altereing 1 of 5 instead of all 5 at once with the same ID caused conflicts?
    LVL 2

    Accepted Solution

    If you just want to test, take one of the APs and change the SSID, then add WEP.  On the clients, use this new SSID with this WEP key.

    Once you have checked that WEP works fine, enable WEP on all APs and configure WEP on all client devices.

    Keeping the same SSID and having a mixture of WEP and non-WEP APs will result in unpredictable behaviour, because the cliens associate with the first AP they find in their channel scan (not necessarily the closest one).

    With the Aironet 1100 b/g APs, you can specify up to 16 virtual APs, each with their own security profile.  This means that you can simultaneously have two SSIDs configured on all access points, one with WEP and one without.  This will allow you migrate the users slowly without taking down the unmigrated ones.

    Two things to note about WEP:
    1> WEP64-bit is compatible across different brands, WEP128-bit might give you some compatibiliy issues.
    2> Same goes for HEX vs. ASCII keys.  the 802.11 standard specifies HEX keys, and these should be used.  ASCIII keys should only be used when all your equipment (APs + clients) is from the same vendor.

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