Selective forwarding with dhcrelay - PXE Master Server

[Chuck Anderson]

On Sat, Oct 11, 2008 at 09:09:29AM -0400, Alex Burger wrote:
>
> I have created a patch for dhcrelay to allow you to specify which server  
> to forward to based on the MAC address of the requesting client.  This  
> allows you to have clients on the same subnet that require different PXE  
> servers to function.  For example, if you use Microsoft RIS and Altiris  
> on your network you would normally have to have the clients on different  
> subnets as you can not have two PXE servers on the same subnet.  With  
> the patch, you could have all the clients on the same subnet.  Only the  
> PXE servers need to be on a different subnet.

We got this to work without hacking the relay.  The trick is to relay 
all DHCP requests to a real DHCP server, and not any PXE servers.  
Then have the DHCP server hand out the PXE options to point the 
different clients to the different PXE servers for "stage 2" where 
they download their boot files.

e.g. in dhcpd.conf:

class "Class-Windows-Lab-PXE" {
        match hardware;

        filename "\\boot\\x86\\wdsnbp.com";
        next-server 10.1.2.3;
}

subclass "Class-Windows-Lab-PXE" 1:00:24:4F:C2:66:FE;