@chanstag A proper dhcp/pxe boot process should be this.
PXE client - Discover DHCP Server - Offer PXE client - Request DHCP Server - ACK.That second pcap is discover, offer 1, offer 2, discover. Meaning that the pxe client didn’t get what it needed to even get an IP address.
So a couple things I’ve gleaned from looking at the pcap.
If your dhcp server is running on your router, its not responding to the dhcp discover from the pxe booting computer. You have a non-fog created dhcp server running on the fog server. Its responding with an IP address but its not sending the boot file or next server information. The FOG created dhcp server will send the proper boot information. You have dnsmasq installed on the FOG server, and it IS responding correctly. But because there is a dhcp server also running at the same IP address the target computer is getting confused and taking the dhcp offer and not the proxy dhcp offer. Your target pxe booting computer is a uefi type BC (00007). Not really important, but dnsmasq should be sending ipxe.efi to the target computer so it can boot.