NetBoot

Most computers come with ‘firmware’. This is a built-in mini OS, embedded in the chips, that’s just smart enough to start things up and hand-off to something more capable.

That more-capable thing is usually an Operating System on a disk, but it can also be something over the network. This lets you:

• Run an OS installer, such as when you don’t have one installed yet.
• Run an the whole OS remotely without having a local disk at all.

PXE

The original way was Intel’s PXE (Preboot eXecution Environment) Option ROM on their network cards. The IBM PC firmware (BIOS) would would turn over execution to it and PXE would use basic network drivers to get on the network.

HTTP Boot

Modern machines have newer firmware (UEFI) and it includes logic on how to use HTTP/S without the need for add-ons. This simplifies thigns and also solves potential man-in-the middle attacks. Both methods are still generally called PXE booting, though.

Building a NetBoot Environment

Start by setting up a HTTP Boot system, then add PXE Booting and netboot.xyz to it. This gets you an installation system. Then proceed to diskless stations.