phpDHCPAdmin demo

[Jeffrey Hutzelman]

--On Sunday, October 12, 2008 09:35:50 AM +0100 Simon Hobson 
<dhcp1 at thehobsons.co.uk> wrote:

> Glenn Satchell wrote:
>> option broadcast-address can be derived from the subnet declaration?
>> It is inherited from that scope - and if the two are different, well
>> your configuration is not correct.
>>
>> subnet a.b.c.d netmask e.f.g.h {
>>   option broadcast-address e.f.g.h;
>> }
>
> Must have been a long day for you Glenn :-)
>
> Yes broadcast address can be derived, but it's more like :
>
> subnet a.b.c.d netmask e.f.g.h {
>    option broadcast-address i.j.k.l;
> }
>
> where i.j.k.l = a.b.c.d OR NOT(e.f.g.h)
>
> Of course, the option subnet-mask should be the same as in the subnet
> declaration.

Except, of course, when it's not, such as when trying to prepare clients 
for a routing change that will be made later (in which case you'll have a 
longer subnet-mask than the declaration would imply), or when the 
shared-network in question has a router doing proxy arping (in which case 
you'll have a shorter subnet-mask).

But these are unusual configurations, and I would not recommend them to 
anyone who does not know what they're doing.

-- Jeff