LinuxQuestions.org

LinuxQuestions.org (/questions/)
-   Linux - Networking (http://www.linuxquestions.org/questions/linux-networking-3/)
-   -   PXE booting using Windows Server 2008 DHCP Server (http://www.linuxquestions.org/questions/linux-networking-3/pxe-booting-using-windows-server-2008-dhcp-server-875690/)

fantasygoat 04-18-2011 01:43 PM

PXE booting using Windows Server 2008 DHCP Server
 
I'm stuck in a situation where I have an existing Windows Server 2008 DHCP server that I can't replace as all the workstations in the company run off of it.

I've configured it as found on the net with the Linux boot server and the pxelinux.0, but every time the machine boots with PXE, I end up in a Windows install instead of the kickstart session I'm hoping for.

Clearly Windows is doing something but I can't find any clues online how to circumvent it. I have no need of PXE booting in Windows so disabling that is not a problem.

Any ideas?

Dazed_75 04-18-2011 03:48 PM

I'm not sure what your current configuration is, but it sounds like you somehow have it set up to boot the machine and the machine boots windows server. For lack of information, I cannot tell you what is currently wrong. But I can tell you what might be your solution.

Probably what you want is a separate (possibly virtual) PXE server with you altering the DHCP server on the windows machine to direct PXE boot requests to the (probably Linux based) PXE server. Most PXE server setups tell you to do it that way.

You COULD also let the PXE server run a DHCP server but make sure it is offering leases in an IP range that is part of the local net but does not conflict with the addresses handed out by the Windows server. For example, the Windows server hands out addresses 192.168.1.50-149 and the PXE server hands out 192.168.1.150-199. The Windows server is booted 1st so it is the DHCP server when the PXE server boots (unless you set it up as a static IP).

Later when client machines boot up, those trying a PXE boot make a DHCP request which includes PXE service. Both DHCP servers make a DHCP offer but only the PXE server offers the PXE service so the client machines choose it. Clients making not requesting PXE service may end up with a lease addresws offered by either one but both use the windows server as gateway and DNS resolution because the PXE server uses it when it boots up and passes that info on.

Hope that helps!

fantasygoat 04-18-2011 03:50 PM

Yes, I have a Linux PXE server running. I've put that server's IP in the Boot Server setting on the Windows server, but it's not working.

Having two DHCP servers running on the same physical network is a major no-no, even if they offer different subnets. I do not want workstations getting server IPs!

Dazed_75 04-18-2011 04:32 PM

Quote:

Yes, I have a Linux PXE server running. I've put that server's IP in the Boot Server setting on the Windows server, but it's not working.
Do you mean what you said in your initial message that the Windows server was rebooting? Or do you mean that the PXE client is not being directed to the PXE server. The former is the question I can't answer without more details. For the second, watch the PXE client machine to see if it is being told the PXE servers IP as the DHCP Offer so that it tries to boot from there. If it is still trying to boot from the Windows server, you have not set up the Windows DHCP server correctly.

Quote:

Having two DHCP servers running on the same physical network is a major no-no, even if they offer different subnets. I do not want workstations getting server IPs!
Actually, having multiple DHCP servers on a LAN is extremely common in commercial environments. But they MUST offer IPs in separate ranges in order to prevent conflicts. If you are wanting servers to be in a separate, or private subnet that is another reason one might use separate DHCP servers though it seems an improbable scenario so I think I am not quite understanding your statement.

fantasygoat 04-18-2011 04:38 PM

The Linux clients are booting into a Windows install, so the Linux clients aren't being given the Linux PXE server's IP. I'm assuming this is an issue on the Windows DHCP server, hence my original question wondering if anyone has managed to get a Server 2008 server to provide Boot Server properly to Linux clients.

It's impossible to see on the clients as the boot sequence goes by too quickly to catch.

As for multiple DHCP servers on the same network, how do you prevent them from colliding? I mean, they'll both answer requests for IPs, and whoever gets there first wins. What is more common is that someone plugs a router in and its local DHCP server clobbers the proper one and no one gets any IPs.

Dazed_75 04-18-2011 04:55 PM

Quote:

The Linux clients are booting into a Windows install, so the Linux clients aren't being given the Linux PXE server's IP. I'm assuming this is an issue on the Windows DHCP server, hence my original question wondering if anyone has managed to get a Server 2008 server to provide Boot Server properly to Linux clients.
You may be right about it being a Microsoft-ism. Take a look under cause on:
http://support.microsoft.com/kb/259670
I they really won't do that and the router solution they mention is not useful, you may NEED to use dual DHCP servers.

Quote:

It's impossible to see on the clients as the boot sequence goes by too quickly to catch.
One way to make it more visible is to download a gPXE Boot CD image and temporarily boot from that CD which is slower but you can se it and even use a Ctrl-B to interrupt the process (goes to a terminal but you can also Ctrl-Alt-Del from there to reboot). Anyway, you can see the IP being used.

Quote:

As for multiple DHCP servers on the same network, how do you prevent them from colliding? I mean, they'll both answer requests for IPs, and whoever gets there first wins. What is more common is that someone plugs a router in and its local DHCP server clobbers the proper one and no one gets any IPs.
There should be no collisions if the two (or more) DHCP servers are offering connections if different subnet ranges as indicated in my earlier post.

Actually, it is normal according to the DHCP Standard (who knows how much of that Microsoft adheres to) for there to be multiple DHCP offers (up to some number I forget) from different DHCP servers in response to a single DHCP request by a client. The client is supposed to choose the best match to the service(s) requested not just use the first reponse. If all offer the requested service(s) then the client is free to choose any which is likely to be the first or the last received.

jefro 04-18-2011 05:25 PM

I think your corporate structure has more than you think. There is a window image server already?

Get past that with gpxe.

patpatpat 06-07-2012 06:47 AM

On these cases splitting the DHCP job is the best strategy.
A regular DHCP service administers the IPs and a proxyDHCP service provides the booting information

Serva uses that and it works like a charm,
read here
http://www.vercot.com/~serva/howto/WindowsPXE1.html


All times are GMT -5. The time now is 03:59 PM.