@vijaybomble OK great you have the prerequsites in the proper configuration.
If your fog server is your dhcp server, and your pxe booting client are on the same subnet, lets use your fog server to capture what is pxe booting is doing on your network. You can use tcpdump on the fog server to capture only the traffic we need. I have a tutorial here on what you have to do: https://forums.fogproject.org/topic/9673/when-dhcp-pxe-booting-process-goes-bad-and-you-have-no-clue
Upload the pcap to this forum or use a private google drive and im me the link and I’ll take a look to see what is going wrong.