[gPXE] DHCP Client ID in gPXE 1.0.0?

[Michael Brown]

On Wednesday 17 Mar 2010 09:20:32 Steven Shiau wrote:
> The problem is, the MAC addresses might change. For example, if you are
> testing some new machines, especially in the massive deployment, batch
> to batch, you won't like the idea to input the MAC addresses in the
> dhcpd config file.
> 
> My question is, why gPXE differs in the DHCP Client ID? Why it's not the
> same with etherboot or PXE?

gPXE passes the link-layer address in the DHCP client identifier (as per RFC 
2132 section 9.14).

This is a legacy of Infiniband support; it used to be the case that the client 
identifier was the only way to identify an IPoIB DHCP request, since the 20-
byte IPoIB MAC address is too long for the 16-byte chaddr field (see RFC 4390).  
However, gPXE now fills the chaddr field with the 8-byte Infiniband GUID, so this 
problem no longer exists.

gPXE continues to set the DHCP client identifier for backwards compatibility.

Michael