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I want to give our Windows guy a way of easily PXE booting machines for deployment by plugging his laptop into one of our site networks. I've set up a TFTPD32 configuration which does just that, and our normal DHCP server ignores the PXE DHCP requests due to them having some magic flag, so this part works as desired. However I'm not sure how to configure TFTPD32 to only respond to PXE DHCP requests (the ones with the magic flag) and ignore all normal DHCP requests (so that the production machines don't get a non-routed address from the PXE server).

How do I configure TFTPD32 to ignore these non-PXE DHCP requests? I know this is possible with ISC DHCPD (by allowing only requests from PXEClient vendor ids), but a nice windows GUI would be preferred.

Or if TFTPD32 can't do this, is there another equally easy to use piece of software that he can run on his Windows laptop? Since the TFTPD part is working fine, a DHCP server with the ability to serve PXE only would do.

Worst case I'll have to set up a virtual machine with ISC DHCPD, but I'd much prefer a small, simple solution.

I'm not interested in solutions that involve using the existing DHCP servers or separating machines on the network for deployment, the whole point is to be simple and stand-alone.

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3 Answers 3

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Just to close this, the simple answer here is that TFTP32D can't do this, or at least couldn't at the time. I ended up giving them a preconfigured VM image with ISC DHCPD and no access to the VM so they could only start/stop the thing.

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It's not a "magic" flag, but a defined one, the DHCP discover includes options 60, 66 and 67 http://blogs.technet.com/b/dominikheinz/archive/2011/03/18/dhcp-amp-pxe-basics.aspx http://www.intel.com/support/network/sb/CS-028533.htm

You could have the ISC DHCP server running in a VM on the technicians laptop.

You could also use the Microsoft DHCP server to service PXE clients, and then if you wanted to restrict access use the pxelinux menu system with a password.

If you used Windows Server on the laptop, you could run WDS and wdslinux on the laptop.

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That solution was already linked to in the question. Also: catb.org/jargon/html/M/magic.html –  Ingmar Hupp Apr 14 '13 at 11:44

I don't think you can do this.

The only viable workaround I see is disable the DHCP server altogether in TFTPD32 and just use it as the TFTP server. (I would do that anyway. 2 DHCP servers in the LAN is asking for problems.)

But that would mean you will have your normal DHCP server specify the ip address of the TFTPD32 server to those clients instead of ignoring them. (You are already separating them so you know how to do this.)

If the laptop can be in multiple subnets just give it a reservation in each one so you know which ip address to offer in each of those subnets.

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It's definitely doable with ISC DHCP (see danhomolka.wordpress.com/how-tos-mainly-technical/… for example, specifically class "pxe" and allow members of "pxe"). I'd prefer not having to set up a VM with that though, if possible. –  Ingmar Hupp Nov 14 '11 at 18:56
    
@Jeff Strunk: Thanks for edits. It was written in haste and that showed. –  Tonny Nov 14 '11 at 20:41
    
The idea is to have two DHCP servers on the same LAN. Which works fine if one of them only serves PXE requests and the other one everything else. There are no conflicts this way. I couldn't figure out how to keep TFTPD32 from serving non-PXE requests though, so I've done it on a Linux VM with ISC dhcpd instead, and it's working just fine (regular DHCP server serves regular DHCP requests, my VM on the deployment server serves the PXE ones for an entirely different subnet used for TFTPD). –  Ingmar Hupp Feb 24 '12 at 0:32
    
@Ingmar: If you can control both the DHCP servers it can be OK. (I'm doing the same thing actually). I wouldn't give a DHCP server in the hands of a developer on my sites. To much potential for havoc if they mess with the configuration. –  Tonny Feb 24 '12 at 19:01
    
They're not developers, they're part of our IT staff needing this to PXEboot for the bulk of a Win7 client rollout. They just get to start/stop the VM, no login. I'm not just handing out rogue DHCP servers to anyone that asks ;-) –  Ingmar Hupp Feb 24 '12 at 19:57

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