Boot an Ubuntu ISO via iPXE

[NiKiZe]

Yes there are several posts - and it is in the FAQ as well.
The answer is that booting an ISO as is, is unlikely to work.
if you use sanboot, with an iSCSI server, it might be possible - but with http or https it's not possible, the other option is using memdisk (for legacy pcbios) but that requires other hacks in the isos init scripts.

You should extract kernel, initrd and squashfs from the ISO and follow the distros docs for PXE boot ... hower a good place to look for examples is https://github.com/antonym/netboot.xyz