[ILUG] pxeboot & dhcp

[Lars Hecking]

Darragh Bailey writes:
> I asked before on the irc channel whether there was anyway to do
> pxebooting where I had my linksys box currently providing the dhcp
> without completely changing my network, and no one was able to 
> provide an answer. Those that responded thought that I would have to
> change to having my PC do the dhcp.
> 
> I've since found that you can set additional DNSMasq options on the 
> dd-wrt that allowed me to specify my PC to act as a pxeboot server 
> without having to have dhcp run on my and disable it on the router when
> trying to netboot a laptop (doing some rescue work on a laptop missing a
> critical file and having a broken CD/DVD drive).
> 
> Some others may find the following option useful, enable DNSMasq for
> DHCP and add the following line to the Additiona DNS Options under
> Administration -> Services:
> dhcp-boot=pxelinux.0,<machaine name>,192.168.1.10
> 
> I left the section for machine name blank in my case, it's not actually
> necessary. Detailed man page link:
> http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html
> 
> 
> In any case, I was doing some reading on syslinux and from reading it I
> seems that since bootp is an extension and a separate request that it
> might be possible to have 2 dhcp instances running within the same
> network. 1 which takes care of assigning addresses, i.e. the instance
> running on my linkSys wireless device and should basically ignore any
> bootp requests, and a second instance that I can start on my PC along
> with tftpd only when I need to, and is configured to only handle bootp
> requests.
> 
> I haven't looked at it closely enough, so I don't know if dhcp even 
> allows you to do this as part of the protocol standard and additionally 
> whether it is then actually implemented to allow this for the dhcpd that 
> would be installed on my PC.
> 
> Anyone tried anything like this before?
 
 I'm not sure I understand. What would you need a second dhcpd instance for?
 Ok, I'm not familiar with the Linksys' dhcp, but ISC dhcpd does implement
 bootp. I have in fact done something similar recently (installed OBSD on a
 Soekris 5501 through the serial port [as control channel] via pxeboot).
 The dhcp server and the tftp server are two separate machines. dhcpd is
 configured

...
group {
        filename "pxeboot";
	# this is the tftp server
        next-server 192.168.1.1;
        host soekris {
                hardware ethernet 00:11:22:33:44:55;
                fixed-address 192.168.1.100;
        }
}
...

 Not sure this helps :)