ap 1200 no ip from dhcp when wep enabled

[gary]

I have recently set up an AP 1200 access point when i try to connect to the access point with a lap top i can not obtain an ip address from our dhcp server if i remove wep encryption it works fine ?? any ideas

[DELL ACORD]

Are you running short or long preambles on the A/P?

Are you running Aironet Cisco Extensions on the A/P?

I had some issues with misconfiguration between the A/P and the client with the preambles. Also, I have seen issues with the Cisco extensions with non-certified Cisco extensions equipment.

Hope this helps.

DTA

[gary]

I don't even know what long or short preambles are ?

i am not running any extensions that i know about, i am working on a pretty standard configuration so have not really set up anything except changed my ssid from the default tsunami and tried to enable wep encryption.

Thanks for your help and rapid response

[andrew.brazier]

I've run into this problem serveral times. What I've found is that although you apply the WEP key via the browser interface it doesn't actually write it into hte running config. BUT even though your client has a WEP key and the AP doesn't the AP will still list your client as "associated" but with an IP of 0.0.0.0 which is misleading to say the least.

Solution; telnet to the AP and make sure the WEP key is shown in the running config, if not re-apply either via the cli or the browser and check the config again.

[gary]

Thanks for your reply i fixed the problem in the end i had my wep key in the wrong place in the config.

[gary]

just found the info and i am running short preambles

and i have aironet extensions enabled

[andrew.brazier]

Hi there,

I've had this problem numerous times and finally got to the bottom of it. Check the raw config.txt of the AP, you may find that part of the WEP config is missing (usually the key) although it's shown in the browser GUI. Re-enter the details in the browser and re-save, check the config.txt and it should be there and you should then get a DHCP'd IP address.

It's really misleading as the AP shows the client as "associated" which is dumb because how can the client associate with incorrect credentials? Crap error message Cisco!