host statement scope rules (ISC DHCP 3.0.5b1)

David W. Hankins David_Hankins at
Mon Jul 31 23:03:44 UTC 2006

On Mon, Jul 31, 2006 at 11:18:19PM +0100, Simon Hobson wrote:
> Is there any real reason to need the inheritance of putting a host 
> declaration within a subnet ? I guess it comes down to, will the host 
> inherit anything that it wouldn't have inherited anyway by virtue of 
> being 'put there' as the server allocates it to a subnet for lease 
> allocation purposes ?

That's just it: the subnet that's found and passed into other
structures doesn't seem to have any affect on the inherited values.

It's also really unclear to me right now what happens with host
records with no fixed-address statements.

> "Whilst host statements may be placed within a subnet or 
> shared-network declaration, this was not an intentional capability 
> and its use is deprecated."

I don't think I'm ready to call this behaviour deprecated yet.

I'm willing to call the current behaviour a bug, but not one that
we can fix in maint (and not one we can fix, it looks, in 3.1).

That is, a flaw in design rather than a flaw in implementation.

> takes precedence ? It strikes me that having a host that can be given 
> options relevant for a different subnet is a tad dangerous - I wonder 
> if it's been responsible for some of the "the client got the wrong 
> value" queries on the list ?

Quite probable.

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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