host declaration restrction (Re: ISC DHCP 3.0.5b1 has been released!)

[Ken Roberts]

On Fri, 2006-07-28 at 13:08, John Wobus wrote:
> On Jul 27, 2006, at 6:30 PM, David W. Hankins wrote:
> > - Host declaration hardware addresses and client identifiers may only 
> > be
> >   configured once.  dhcpd will now fail to load config files that 
> > specify
> >   multiple identifiers (previous versions would silently over-ride the
> >   value with the later configured value).
> 
> If I understand correctly, this says that before 3.0.5b1, you could use 
> this:
> 
>    host host6 { hardware ethernet 00:12:3F:7C:B7:29; fixed-address 
> 10.128.137.78; }
>    host host6b { hardware ethernet 00:12:3F:7C:B7:29; fixed-address 
> 10.128.55.79; }
>    host host6c { hardware ethernet 00:12:3F:7C:B7:29; fixed-address 
> 10.128.55.44; }
> 
> In 3.0.5b1, you would need to use this:
> 
>    host host6 { hardware ethernet 00:12:3F:7C:B7:29; fixed-address 
> 10.128.137.78,10.128.55.79,10.128.55.44; }
> 
> Is this right?  If so, it'll generate some reengineering work for us.
> 
> John Wobus
> Cornell Univ CIT
> 
> 


I hadn't known about the multiple fixed-address list until this thread,
but one thing I think would be handy here is a wildcard like this:

host joebob {hardware ethernet 00:12:3F:7C:B7:29; fixed-address
1.2.3.4,1.2.4.4,*;}

This would allow host6 to show up on any subnet (if it's a laptop for
example) but if the server finds an address appropriate to the subnet it
will use a fixed address.  This also lets you keep this host as a single
address, so you would never need more than one host line per real host.

Another interesting idea would be this:

host joebob {hardware ethernet 00:12:3F:7C:B7:29; fixed-address
1.2.*.[3-17,19];}

Come to think of it, I can't really see a valid reason for that second
part unless you mapped the fourth quadrant to different firewall access
by range and defined the authority through the host clause.

However, the first example would offer a feature that I think a whole
lot of people would want.