Re: [dhcwg] lease query question

"Cosmo, Patrick" <Patrick@incognito.com> writes:

> >Thus, knowing that an address is reserved, but
> >not currently in use, doesn't seem to be info the 
> >relay agent really needs. Am I missing some other 
> >important detail here?

> Here's one example:

> some relay agents provide an "Host Authentication" feature where they only
> fwd data from an device using an IP address that the device "really does
> own". This is an attempt to prevent IP spoofing. The relay agent determines
> who "owns" an IP address (who was actually leased the address) by gleaning
> the DHCP messages that pass through it, or through DHCP lease query.

I understand and agree with everything so far.

> In the case where a device is manually configured with an IP and is
> not performing DHCP, the DHCP service may be configured with a
> "static address" for the device to indicate that the device really
> does "own" that IP address. The relay agent can determine and
> recognize this fact through the use of DHCP lease query.

So, the client  isn't using DHC, but we're going to configure the DHC
server about that client anyway and the relay agent is going to use
leasequery to get info from the DHC server about those  addresses,
even though DHC (as in the RFC 2131) isn't even being used for these
addresses?

Is this indeed part of the problem statement?

I'll note also that the above problem can't be solved by DHC gleaning,
since the client isn't using DHC. So, the above isn't just about
restoring gleaned information after losing state.

But having said that, couldn't the DHC server just respond with "I
have a lease" for the hardcoded configuration information, even if it
(in some sense) doesn't? What the relay agent presumably cares about
is whether an address is in use on a certain link. It doesn't really
care _how_ the DHC server knows about those addresses. Right?

Thomas
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