Free Options

[Jeffrey Hutzelman]

--On Wednesday, January 09, 2008 07:43:09 PM +0100 Ruben Rios 
<ruben_roller at yahoo.es> wrote:

> Hi there,
> I have been searching on DHCP Options because I would like to use some
> private ones for my own private use. Can anyone tell me which of them can
> I use for that? I thought I could use any, but while eavesdropping on my
> network I have realized some of these options are already in use ( 249:
> Classless static routes; 252: proxy autodiscovery). Are there any others
> I should avoid using? Thanks a lot!


For truly "private use"; that is, uses which are defined by the 
administrators/network managers at a particular site for use within that 
site, you can use option codes 224-254; see RFC2939, RFC3942, and the 
registry at <http://www.iana.org/assignments/bootp-dhcp-parameters>.

For vendor-specific options; that is, something where you will be shipping 
a hardware or software product (commercially or otherwise) which will 
transmit and/or respond to an option you define, your choices are to use 
the vendor-options option (option code 43), either with or without the 
encapsulated vendor options format described in RFC2132 section 8.4, or to 
obtain a publically-assigned option code by standardizing your option 
through the Internet standards process.


Regardless of the approach you use for selecting an option code, the ISC 
DHCP server can be configured to use new options without making any changes 
to the source code.  See the "DEFINING NEW OPTIONS" section in 
dhcp-options(5).

-- Jeffrey T. Hutzelman (N3NHS) <jhutz+ at cmu.edu>
   Carnegie Mellon University - Pittsburgh, PA