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User De-authenticates every few minutes

Hello all,

One of our users gets de-authenticated every few minutes from our Cisco 1240AG APs. He is using a D-Link DWL-AG530 NIC. I do have Cisco Aironet extensions enabled on the AP.

Any ideas will be appreciated.

Here is the Log entry from the AP Mar 7 16:32:54.608 Information Interface Dot11Radio0, Station X Associated KEY_MGMT[NONE] Mar 7 16:32:52.305 Information Interface Dot11Radio0, Deauthenticating Station X Reason: Previous authentication no longer valid Mar 7 16:32:52.305 Warning Packet to client X reached max retries, removing the client

Thanks.

Reply to
Omar
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This behavior could have different causes:

  • Radiowave interference
  • Layer 2 deauthentication attacks
  • Bruteforce attacks on the authentication key depending on the mechanism in use (MIC protects against this kind of attacks in WPA mode by kicking off clients for the duration of 1 minutes to reauthenticate themselves)

Best solution in my opinion is to find out the most probable cause by testing with the hardware in different rooms/buildings, running a wireless sniffer to inspect what is going on in the air and, if possible, elimate the cause of the disconnects.

Reply to
Leander de Graaf
  1. What IOS version is running on AP ?

  1. What firmware version is installed for the D-LINK NIC NIC ?

  2. Using the D-LINK NIC utility, what is the signal strength seen by the D-LINK NIC ?

  1. How far are from the AP is the PC with D-LINK NIC ?

  2. Are there other PC's using the same type of NIC in your network ?

  1. Has a different type of wirless NIC been tried in the troubled PC ?

Reply to
Merv

12.3(11)JA

Don't have it at the moment

The signal strength is excellent as the AP is not too far from the PC.

About 15 feet

BTW, I updated the driver on the D-Link card and that fixed the issue. Thanks for the reply.

Reply to
Omar

is running on AP ?

To what driver version ?

Reply to
Merv

is running on AP ?

1.05
Reply to
Omar

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