NetBoot server principle

Requirements

To setup a PXE NetBoot infrastructure you need:

• DHCP server
• DNS server

As you can see on the previous picture, a DHCP server + TFTP server are mandatory.

It's also good to have a DNS server to use names instead of IP @.

Overview of a NetBoot sequence

1. Client broadcasts a DHCPDISCOVER message.

2. The DHCP server responds with:

• the computer IP address,
• TFTP server address (called "next-server"),
• PXE boot filename to load,
• NetBoot root-path values.

3. The client sends a TFTP request to "next-server", asking to retrieve the PXE filename.

4. The TFTP server responds and sends filename to client.

5. Many things here:

• The client executes filename, which is in PXE format.
• The PXE menu will be display so the user can choose which kernel to load
• Then PXE loads the kernel.
• When the kernel executes, the root file system specified by root-path is mounted. If it's a diskless workstation then the client distribution will be mounted in NFS mode.

Diskless NetBoot

The following picture describes the same thing as before in the sequential order:

Note that you have to prepare the image before being able to boot on it. ^^

References

The 1st overview picture comes from the FreeBSD forum: http://www.nl.freebsd.org/doc/handbook/network-diskless.html