On Sun, 20 Sep 2015 01:08:36 AM James Harper wrote:
The actual booting takes place on my server though, and I want the server to supply the dhcp options rather than the router, but still want the router to supply the address etc. This is so I am only editing this stuff in one place, and can script the configuration depending on how I want to boot (boot direct to iscsi with an iscsi filename, or chain via pxelinux where required, etc).
Having a quick look at the protocol I don' t think it's possible as DHCPOFFER's MUST include an IP address for the client, the client can only select one offer to use and the RFC says: Once the network address and lease have been determined, the server constructs a DHCPOFFER message with the offered configuration parameters. It is important for all DHCP servers to return the same parameters (with the possible exception of a newly allocated network address) to ensure predictable client behavior regardless of which server the client selects. The configuration parameters MUST be selected by applying the following rules in the order given below. The network administrator is responsible for configuring multiple DHCP servers to ensure uniform responses from those servers. The clients could be configured to do a DHCPINFORM though to request parameters and the servers DHCPACK responses could have that information. Best of luck! Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC