I have many wireless XP clients that connect to the network via wireless access points using WPA2, AES, and 802.1x authentication using PEAP-MSCHAP V2. The clients are set to validate server certificates and are configured to trust the local root CA. All of the wireless configuration settings and certificate deployment is done through Group Policy.
Most of the XP clients connect to the wireles network as expected, however we have had many occasions when a client will authenticate but fails to obtain DHCP settings. I have observed the flow of traffic between the client and the DHCP server using wireshark and it appears that this only happens when there is a poor quality wireless signal - the client struggles to authenticate, with many packets exchanged, eventually succeeds but then DHCP requests are sent to the DHCP server, which the server also receives, but the responses are not received by the client. I suspect it is the signal quality because as soon as the client is placed close to an access point the authentication process is completed quickly, and the DHCP process is also completed successfully.
Has anyone else had the same issues? Is there any way of improving the clients chances of success of obtaining DHCP settings as we don't want to use static network settings?