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 is iPXE?

Formerly gPXE project, iPXE is an open source PXE implementation and bootloader. It can be used to enable computers without built-in PXE support to boot from the network, or to extend an existing PXE implementation with support for additional protocols. While traditional PXE clients use TFTP to transfer data, iPXE adds the ability to retrieve data through other protocols like HTTP, iSCSI, ATA over Ethernet (AoE), and Fibre Channel over Ethernet (FCoE), and can work with Wi-Fi rather than requiring a wired connection.

YES, (technically) wireless imaging is supported but largely untested.

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