In some cases, we may receive more response from WDS. The stations do not receive any response from the TFTP server and fall out in timed out.
The problem occurs when the DNS server service and WDS are on the same machine. The procedure for circumventing the problem differs between Windows Server 2008 and Windows Server 2008R2.
For Windows Server 2008
Launch the WDS console (Windows Deployment Service). In the server properties, network tab increase the UDP port range and Restart WDS services
For Windows Server 2008 R2
Launch Regedit and search for the following key.
Modify the value of UdpPortPolicy (add a DWORD32 if absent) and insert the value 0. Restart the WDS Service.