force to only accept hardware address as dhcp-client-identifier

David W. Hankins David_Hankins at isc.org
Tue Jan 29 19:50:38 UTC 2008


On Tue, Jan 29, 2008 at 07:07:08PM +0000, Simon Hobson wrote:
> What happened to the proposal to add a config option to control the 
> primary key selection criteria ? Did it make in into any of the 
> current releases, is it still on the 'to do' list, or did it get 
> dropped ?

it got added and dropped two or three times.  it's still on the 'to
do' list.

the current thinking on how to implement this is to provide a way to
over-ride the option value.  this is more generic and may apply more
directly to mixed RFC 4361 environments.  the final code would
ignore an over-ridden option content that was zero length.

> Also, adding the ability to use this value (ie the selected key) as a 
> client selector in host statements would also deal with the "assign 
> address to client by option-82" that comes up fairly regularly.

in the dhcp-4 work, we were trying to figure out how people would want
to describe a host {} statement for a DHCPv6 client.  i'm not sure
we're done with that, but we had to add a way to identify a host
record based upon an arbitrary option contents, so you could get the
MAC address out of a DOCSIS-3.0 vendor class option.

it doesn't currently work for v4, but all that's really necessary is
adding a few lines of code to perform the by-option-contents lookup
somewhere in DHCPv4 message processing.

so that's another, more low hanging fruit, for assignment by option
82 contents (but requires you assign a fixed address for every port
rather than assigning dynamic addresses to switch ports as they come
up).

-- 
Ash bugud-gul durbatuluk agh burzum-ishi krimpatul.
Why settle for the lesser evil?	 https://secure.isc.org/store/t-shirt/
-- 
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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