I've implemented 802.1x on my network. All workstation are Windows XP.
In some of them, when I plug the machine at the network, the switch doens't send the EAP request imediatelly... the workstation DHCP request occurs first, and after this.. the EAP request happens.
Is this a normal behavior?
Is there a way to force the switch send the EAP request before the workstation generate DHCP request?
From what I have seen the switch will send the EAP as soon as the port comes up. This maybe that the PC and the switch are trying to send packets before the port is really completely active.
Make sure you have portfast on the switch since this know to cause issues. You can also attempt to change the dot1x timeout tx-period to something less than the default of 30 seconds. You have almost a 30 second delay in your trace.
A debug on dot1x and ip packet while you capture may indicate if the pc and the switch see things the same way.