"unsetting" global options for a host

[Rick Coloccia]

Glenn, I'm working on a test scenario to find out if what you suggest 
will work. I suspect it's up to the client whether it treats an option 
with a null value the same way as an undelivered option.  Thanks!

-Rick

On 1/31/2012 6:26 AM, Glenn Satchell wrote:
> On 01/31/12 20:39, Simon Hobson wrote:
>> Christian Kratzer wrote:
>>
>>> why don't you just put the hosts in different groups depending on the
>>> options they need. Sounds like you know the specific hosts you need
>>> to exluded so why not just list them in a group.
>>
>> Not sure about the OP, but in the general case it's more likely to be a
>> case of "all clients whether specified by host statements or not get
>> option X - except for ..."
>>
>> So it makes sense to specify the option in the global scope so it
>> applies to all dynamic clients, in all subnets & pools, as well as
>> defined hosts. The problem then is unsetting an option for a small
>> number of clients - which might not have fixed addresses. So it would be
>> ideal if the following were possible :
>>
>> option X blah ;
>>
>> subnet ...
>> range ...
>> }
>>
>> group ...
>> unset option X
>> host ...
>> hardware ...
>> host ...
>> hardware ...
>> }
>
> I haven't tried this myself, but what about setting the value to 
> either a null string, or a null byte? I think there is a difference 
> between an option that is not defined, vs an option with a null value, 
> but it might just work. For example:
>
> option X \000;
>
> Plug this into Simon's example above and see how you go. The client 
> might just decide that a null value is the same as not set. Or it 
> might not :(
>

-- 
Rick Coloccia, Jr.
Network Manager
State University of NY College at Geneseo
1 College Circle, 119 South Hall
Geneseo, NY 14454
V: 585-245-5577
F: 585-245-5579