At 11:36 PM -0500, 01/27/2001, Jay R. Ashworth wrote:
On Sat, Jan 27, 2001 at 11:16:00PM -0500, Eric Sobocinski wrote:
It's possible theoretically but not in the real world. Nice idea though. Your major headache is that DHCP isn't defined to work that way. :-) Right now the DHCP model assumes that any static mapping can depend upon a hardware identifier, usually the MAC. It wouldn't be that hard to define an appropriate DHCP option to substitute something more arbitrary like a VC identifier, but to my knowledge no one has done so.
Perhaps I'm misunderstanding either you, Eric, or the situation, but DHCP client can supply a host name, can they not? And I thought servers could use that to look up for a fixed address.
Yes, it's configurable, rather than fixed, but at least it's *there*.
Would this not solve the gentleman's problem?
Hmmm, you're right. It gets supplied as a form of the "client identifier", but I've never seen a host name used, and somehow I hadn't notice on my recent reading of RFC 2131 that it even gives "DNS name" as an alternate possible use of the "client identifier" option. [RFC 2131, page 8 et al] I bow before your power of recollection. I'm left wondering how one would enforce correct configuration of host name as the client identifier? What would prevent one customer from configuring a machine to steal someone else's static address? That wouldn't be much use for getting a second address but it would make for a dandy denial of service against the "someone else". I suppose that, as long as the client identifier can be arbitrary, that one could issue a difficult-to-predict client identifier for each IP address. Tell the customer it's their IP address contract number? You're right, at least it's already there, even if the ISP discovers they have to modify some DCHP client software in order to implement it. (I'm humbled) --eric