In researching this question, I’ve found that there seems to be some debate as to whether or not your DHCP options of 66 and 67 need to be set. In this senerio, Microsoft Support says neither. Your client performing a network boot will proceed thru the normal method of acquiring an address through DHCP. Once that is done, it will start the process over again, this time looking for a PXE server. The WDS server should pick this up (if it is the same subnet) and forward its information on the requesting client.