Supported format for Client Identifier.

David W. Hankins dhankins at
Tue Jun 16 21:17:21 UTC 2009

On Tue, Jun 16, 2009 at 11:01:13PM +0200, sthaug at wrote:
> It is backwards compatible *except* for the fact that the "standard"
> DHCPv4 format of hardware type (1) followed by the 6 byte MAC address
> is no longer permitted, as far as I can see.

Yeah, that practice caused problems that the RFC has a section
describing.  Unfortunately, no one has taken a stand on describing
the correct behaviour of the two non-interoperable behaviours we have
seen in this regard, but admonishing the triggering behaviour is a
kind of victory.

> some people *really* want to be able to get the MAC address of the
> client, and the RFC 4161 format removed this possibility.

DHCPv4 is different; you will always have the fixed htype/hlen/chaddr

David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins
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