[ipxe-devel] Fwd: [gPXE-devel] [PATCH]: dhcp: Don't ignore duplicate offers when the dups differ by PXE options presence

Michael Brown mbrown at fensystems.co.uk
Thu Nov 4 18:23:12 UTC 2010

On Wednesday 03 Nov 2010 18:03:25 Joshua Oreman wrote:
> The benefit is in compatibility with Intel PXE, which acts similarly.
> I'm not incredibly attached to the approach, I just wanted to point
> out that this patch might fix the problems with it if we consider
> supporting the same broken setups Intel PXE supports to be a desirable
> thing.

I would consider that to be desirable.  My understanding is that the behaviour 
change required to achieve this affects only ProxyDHCPREQUESTs (not regular 
DHCP, or PXE options obtained in full via a ProxyDHCPOFFER), and can roughly 
be described as:

1. When receiving DHCPOFFERs containing PXE options (option 60 set to 
"PXEClient"), maintain a list of all such offers, rather than only the single 
best offer.

2. After completing DHCPREQUEST/DHCPACK, process the list of PXE offers in 
order of desirability.  For each offer:

  a) if it already contains a boot filename or a PXE boot menu, use it as a
      source of options with no further processing,

  b) otherwise, attempt a ProxyDHCPREQUEST to port 4011 of the offering
      server.  If this times out, move to the next offer in the list.

Does this seem correct to you?


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