PXE, TFTP software selection

So, last time we discussed the general pattern of transferring images over the network. As it was then noted to us to start this process, it is necessary to properly prepare. Immediately make a reservation, my goal does not include an overview of all products working with the PXE protocol. I will conduct a brief overview of the tested products, their pros and cons as part of the task. Let me remind you, this is the first download from the network Ghost, so that he would upload the image of a working operating system with all the necessary software to the machine.

A bit of theory

What is PXE? As part of my understanding, this is the boot environment used for network boot. The network card checks the availability of network boot and receives a boot module via TFTP. In consequence of the 32 MB TFTP limitation, the download takes place in two stages of 16 MB each. In the first pass, the PXE environment is loaded, offering to download a particular OS image from the network. This may be a Linux kernel, pulling further from the network the necessary components or mounting NFS, or, say, a pre-boot boot floppy (our version). There is also the option of downloading iso-images, but I have not worked with it yet.

Our task is to load DOS diskette with network drivers and Ghost.

3com

Bundled software bundled Symantec Ghost Solution Suite. However, it is available for download at 3com. It separates the PXE and TFTP services. The great advantage of the PXE application from this kit is that no additional configuration of the DHCP server is required. No need for classic prescriptions of 66 and 67 parameters, nothing. If the PXE application is running on the same machine as the DHCP server, then the configuration is not required at all, if the Proxy DHCP tick is sufficient for another. And that's all.
')
In this case, the server accepts requests and transfers control to the TFTP server located on the same computer. The TFTP server from this bundle has a classic setting for transferring different images to different MAC addresses, as well as to a certain address group defined by a certain mask, up to sending out the same boot image to everyone.

The advantage of this kit is that it works with arbitrary images up to 16 megabytes. For the transfer of DOS, Ghost, GhostWalker and network drivers, this is quite enough.

Also included in the software package is an editor of these very images of floppy disks.

With this kit, I never managed to load Linux and WinPE. But since it did not fit into our goals. It is curious that when using the checkbox “Proxy via DHCP” it interrupts its own DHCP setting for network booting, checks its BOOTPTAB and if the appropriate template is not found, it transfers control to the downloader written in the DHCP server PXE.

Linux PXELINUX

Recently described the configuration of this option to install Linux. Here In our case, we’ll use not the Linux installer as the boot image, but still unpacking the same image of the diskette with the memdisk directive.

I note that this directive works with normalized disk images. Those. A floppy disk can be of arbitrary size if its architecture is described. Again, a 16 megabyte transfer limit over TFTP floats.

The disadvantages of this option include the need for a proper machine with Linux and still the same DHCP server, which will need to be configured to boot from the network.

PXELINUX from under Windows (TFTPD32)

This is what Wikipedia tells us about this software:
Tftpd32 — , DHCP, TFTP, SNTP Syslog , TFTP , TFTPv2.

I can not call it intuitive to configure, but for a small office that does without a DHCP server, is the best solution. Its main advantage is naturally the presence of a built-in DHCP server. The same PXELINUX environment is used, its configuration is identical for both options. Not a bad man for setting up TFTPD32 here .

Practice

Based on the foregoing and the data that we have a DOS diskette with a Ghost kit (Ghost, GhostWalker, network drivers), we can safely use any of the above software. Having experimented a bit on the network available to me, I preferred the native software supplied with the Ghost suite. In an institution where I am currently working there is a DHCP server, however network boot is already involved to run a diskless Linux version based on a gentle. One time for loading my diskettes, PXELINUX was successfully used, but at a critical moment there was still an uncorrected error (though mainly due to laziness rather than the impossibility of solving the problem). After booting the diskette, the network driver did not correctly get up, and the whole idea died at the root. Downloading from 3-som does not knock down the settings for loading the agents, but simply pushes the priority of their execution for a while.

That's all about downloading from the network. As I promised, at the request of the workers I can draw up step-by-step instructions for using the described software.

The next step will be a small excursion into the esoteric. We will understand what is this ghost.