~ On May 15, 7:13 am, Aaron Leonard wrote: ~ > Hi Bin, ~ >
~ > ~ In Windows, if AP A's WEB key is 1111111111, but I input the WEP key ~ > ~ to 2222222222 and set the IP address to static , say 192.168.1.3. The ~ > ~ windows will connect to AP A, and it reports connect successfully. But ~ > ~ obviously, the data can't transfers. ~ >
~ > Yes, if you have configured 802.11 open authentication with static WEP, ~ > you can and will get into this situation. ~ >
~ > ~ This makes software designers very hard to junior users who don't know ~ > ~ why 'connected' but can't transfer data. Is there way to optimize ~ > ~ this? ~ >
~ > You can monitor your wireless adapter stats. If decrypt errors are ~ > incrementing after 802.11 open authentication/association succeeds, ~ > then it's a good bet that you are dealing with a WEP key mismatch. ~ ~ I doubt how can you get the stats about the decrypt errors? The ~ hardware can only decrypt the data and throw it up to the various ~ stack, it's up to the stack to see is it the data valid. But if you ~ can't get the IP from the AP, who will send you the data to let you ~ check whether it is decrypt error? ~ ~ So it is impossible.
I wouldn't say "impossible".
If you have an API into your wireless adapter's stats, then it may be able to give you access to the decrypt error counters.
There is still an open question as to whether the AP will attempt to send the client any data, after the client associates, in order to trigger the decrypt errors.
I just now tested with a Cisco CB21AG card talking to a Cisco AP, with a mismatched WEP key ... I see that the card is logging a decrypt (or, as it puts it, "Encryption") error every 30 seconds or so.
If you do not have an API into your wireless adapter and do not have access to the AP's control plane, and if you cannot configure shared key authentication, then I agree, you will not know that you are experiencing a WEP key mismatch.
Aaron