From Fedora Project Wiki
PXE chaining
One way to use gPXE is to PXE boot using the machine's PXE client and configure it to show menus using pxelinux where one option is to load gPXE and re-DHCP. gPXE will be recognized by the DHCP server and be given a different boot server and/or filename. (For example, this can be used as a way to jump between two different PXE boot servers.)
The DHCP server has two ways to see the difference between different PXE clients:
Maybe option 77 should be sent as "gPXEqemu" or something like that when qPXE is loaded directly by qemu.
--Abo 14:03, 9 July 2009 (UTC)