10 replies to this topic

[glboot]

Hi, I want to use Tftp32 to boot from net with pxe (boot
various diagnostic tools, OS etc.)

I operate in different environments, most of them
already have a dhcp server configured, so enabling Tftp32
dhcp is not possible.

It's possible to configure Tftp32 dhcp
server to respond only to dhcp request that are pxe dhcp
requests ?

This way, Tftp32 dhcp server will not interfere with
the existing dhcp and allow boot from pxe.

Bye

[erwan.l]

Hi Glboot,

A pxe server is actually a dhcp server + a tftp server.
What about setting up your dhcp server to use tftp32 as tftp server?
This a common setup as dhcp and tftp dont have to be on the same server.

Regards,
Erwan.

[Sha0]

A slight correction: A PXE service has some similar functions to a DHCP service. It understands and uses the DHCP packet format, and can monitor DHCP transactions and participate for PXE clients.

A PXE client sends PXEClient in option 60, which you might be able to make use of.

I do not believe that TFTPD32 can function as a PXE service only. 3Com Boot Services offer a PXE service. dnsmasq can function as one, I believe.

[erwan.l]

Hi Shao,

I'll slightly disagree

PXE is not a service but merely an environement.
You will not find a process or a socket running for PXE.
DHCP is udp/67, TFTPD is udp/69 : these two together will implement the pxe environement.

As quoted there http://en.wikipedia....ion_Environment : "The PXE protocol is approximately a combination of DHCP and TFTP, albeit with subtle modifications to both. DHCP is used to locate the appropriate boot server or servers, with TFTP used to download the initial bootstrap program and additional files."

So basically, by simply specifying option 67 (pxe boot file name), your dhcp server turns into a so called PXE server, provided that a TFTP server runs on the same host.
If not, then you need to specify option 66 poiting to the ip of your TFTP server (tftpd32 for example).

Trust me, I have done that many times

And you are right, a pxe client is basically a dhcp client sending option 60.

Regards,
Erwan.

[glboot]

Configuring the existing dhcp server is not an option (it's not possible)

Maybe it's possible to recognize the pxe dhcp inquiry when there is the request for the "Boot File" or inspecting the PXE-specific options (extended DHCPDISCOVER) of the broadcasted DHCPDISCOVER packet.

[Sha0]

Hi Shao,

I'll slightly disagree

That's fine.

PXE is not a service but merely an environement.
You will not find a process or a socket running for PXE.

Having read the Intel PXE 2.1 specification and as a developer for gPXE and with the countless hours I've poured into supporting PXE users on its and Syslinux' mailing-lists and IRC channels, I recognize the original poster's request quite easily. They are interested in a ProxyDHCP service, since they say

enabling Tftp32 dhcp is not possible.

This is roughly (most commonly) what people mean by a "PXE service," when it is separate from the DHCP service. A ProxyDHCP service on the same box as DHCP can listen on UDP 4011. On a separate box, it's most commonly listening on the DHCP port, as you mention. The poster has since confirmed their scenario. My recommendations of 3Com Boot Services and dnsmasq still apply, as I believe that both offer a ProxyDHCP service. Your statement

A pxe server is actually a dhcp server + a tftp server.

is incorrect. There is not a one-to-one relationship here. "All servers providing DHCP + TFTP are PXE servers and all PXE servers provide DHCP + TFTP" is a false statement. Therein lies the needed correction. DHCP + TFTP do not make a PXE service. A PXE service follows the PXE specification, must include a DHCP service, might include a ProxyDHCP service, might include a TFTP service, etc.

DHCP is udp/67, TFTPD is udp/69 : these two together will implement the pxe environement.

And what about MTFTP, whose port can be dynamically determined during the PXE-boot transactions as outlined in the specification?

As quoted there http://en.wikipedia....ion_Environment : "The PXE protocol is approximately a combination of DHCP and TFTP, albeit with subtle modifications to both. DHCP is used to locate the appropriate boot server or servers, with TFTP used to download the initial bootstrap program and additional files."

"approximately". Yes, a DHCP service and a TFTP service are enough to provide a PXE-booting client with a successful boot. That's not applicable to this request.

So basically, by simply specifying option 67 (pxe boot file name), your dhcp server turns into a so called PXE server, provided that a TFTP server runs on the same host.
If not, then you need to specify option 66 poiting to the ip of your TFTP server (tftpd32 for example).

Trust me, I have done that many times

That makes two of us. With good fortune, some of this information might make three of us.

And you are right, a pxe client is basically a dhcp client sending option 60.

Regards,
Erwan.

Good day to you, as well. I apologize for the confusion by taking into account the context and the common usage of the term.

[erwan.l]

Hi Shao,

I feel stupid now : I had overlooked the fact that you were behind gpxe...
Now me disagreeing look indeed completely arrogant.

Stupid me again : Sorry for trying to look smart

Thanks for patience,
Erwan.

[Sha0]

...you were behind gpxe...

Well, there's a community behind gPXE, anyway, of which I am a part. If you've much PXE experience, please do join the mailing-lists. Your experiences will most likely benefit users with scenarios you've come across.

Thanks for patience,

It's all cool, daddy-o. There's nothing offensive about offering one's experiences and understandings in order to help another person, in my opinion.

Now it would be cool if TFTPD32 had a ProxyDHCP service mode (I won't say "PXE" anymore )... I wonder if Philippe Jounin might be interested in supporting that going forward...

[patpat]

Hi

no time for setting up the web site yet but you guys can give a try to Serva32/64 (free), it includes among other protocols Proxy DHCP (PXE Service).

feedback and bugs reports are welcome

http://www.megaupload.com/?d=3MKB7KZC


Pat

[patpat]

here's the web site...
http://www.vercot.com/~serva/

[gnikolic]

Hello All!

Wanted to ask for some help regarding options in DHCP server of Windows server 2008.
Have two servers and on one of them is SBS2011 with valid DNS and DHCP and wanted to make second Server 2008 as TFTP server with TFTPD64 service.

Read it a lot from internet and somewhere is said that for Cisco VOIP is option 150 and somwhere is writen that it is options 66 and 67.

What options are needed for setup tftp server on another server? What ports it is using for firewall? 69?


Thanx in advice.