IPXE

What is PXE?

Preboot Execution Environment (PXE)

The PXE protocol is approximately a combination of DHCP and TFTP, although with subtle modifications to both. DHCP is used to locate the appropriate boot server or servers, with TFTP used to download the initial bootstrap program and additional files.

To initiate a PXE bootstrap session the PXE firmware broadcasts a DHCPDISCOVER packet extended with PXE-specific options (extended DHCPDISCOVER) to port 67/UDP (DHCP server port). The PXE options identify the firmware as capable of PXE, but they will be ignored by standard DHCP servers. If the firmware receives DHCPOFFERs from such servers, it may configure itself by requesting one of the offered configurations.

What are the differences between the different PXE files?

pxe unloads undi and pxe stack, ultimately the goal, but there's not enough information to allow this to actually work flawlessly everytime

ipxe has drivers, undionly uses the "undi" stack made by the manufacturer.

kpxe unloads just the pxe stack and is the normal file we want in use as it seems to be the best between pxe/chaining I can find without flashing roms.

kkpxe keeps both undi and pxe stacks in place. kkpxe works best for buggy hardware. Only recommended if you're having weird issues with the undionly.kpxe