[SOLVED] PXE booting through different subnet

yuchankit · 08-12-2012, 06:19 AM

My PXE boot server is the default gateway of its PXE client.

From the client, it sees my boot server as 192.168.0.1 . The client also resides inside the 192.168.2.x subnet.

When I set the server to tell the client's PXE to boot from 192.168.0.1, it looks like the client does not see the 192.168.0.1 server although I can ping and even ssh the address mentioned(192.168.0.1).

My setup is currently as follows.

Internet
|
PXE boot server and internet connection sharer.(address 192.168.0.1)
|
Router(address 192.168.2.1) (WAN IP is 192.168.0.2)
|
PXE boot client(s) (address 192.168.2.x) 1<x<256

Here is my /etc/dnsmasq.conf

Code:

dhcp-range=192.168.0.0, 192.168.2.255,12h

dhcp-boot=slackware/pxelinux.0,192.168.0.1

dhcp-option=3,192.168.0.1

dhcp-option=6,192.168.0.1

Hopefully my info is clear enough for now. Care to shed some lights here?

Thank you for reading.

fl0 · 08-12-2012, 06:34 AM

Hi,

to use PXE boot with different subnets, you need some kind of dhcp-proxy/relay , maybe you can use your router for this.
i a cisco router this is called ip-helper.

regrads fl0

yuchankit · 08-12-2012, 10:04 AM

Can I use my server instead to implement the dhcp-relay? If I can, then how? My router does not have dhcp-relay feature.

OldHolborn · 08-12-2012, 11:27 AM

Your server will never "hear" the "shouts" your client sends out.

You need a smarter router or a rethink on your layout/plans.

jefro · 08-12-2012, 11:49 AM

Might be easier to use gpxe/ipxe.

ceh383 · 08-12-2012, 12:23 PM

You could try setting up a SUPERNET

This would allow different subnets to see each other without a need to upgrade your router.

OldHolborn · 08-12-2012, 03:01 PM

It's not the subnetting that's problem it's the presence of the router.

Think of the router as a gatekeeper who will only let people with a ticket (ip-number) get past, in the op's case his ticket office (dhcp server) is on one side of the gate, his ticketless customer (pxe client) on the other.

The dhcp-relay is an extra nice gatekeeper who passes on the request for a ticket.

gpxe/ipxe, these can skip the dhcp part, unfortunately the chainloading pxeclient still needs the dhcp server on the same side of the router as the client - after that the tftp part can be anywhere.

jefro · 08-12-2012, 06:06 PM

No, gpxe can use any internet type topology, ftp, tftp, nfs, http. I may misunderstand the issue but try www.netboot.me.

yuchankit · 08-13-2012, 02:30 AM

@OldHolborn and @jefro : I think I understand what you're saying. Even gPXE works, I must first load PXE(If I don't have a boot medium) before loading gPXE and if I can load PXE from my server, I don't need gPXE. The only compromise I can do is to transfer an iPXE boot image to CD/USB stick and boot from there before booting from my PXE server. iPXE does mention I can skip making boot medium if I flashed my NIC ROM, but I don't think it's possible for my NIC which is AR8152. Thanks for the iPXE suggestion. I learned another thing.

@ceh383 : I've looked at supernetting how-to. It looks complicated to me! Care to shed more lights on this? Thank you.

yuchankit · 08-14-2012, 03:29 AM

I've rearranged my hardware formation. Here is my new HW configuration.

Internet
|
PXE server and DHCP server
|
Switch(The router is converted into switch)
|
PXE and DHCP clients

The problem is solved for now. Thanks for your help so far.