Subject: Use of DHCID in draft-ietf-dhc-dhcp-dns-12

From: [email-masked]
Date: Tue, 27 Jun 2000 13:26:20 -0500

I have several questions concerning the use of the DHCID defined in the
DHCP-DNS interaction draft, draft-ietf-dhc-dhcp-dns-12.txt.

First, in section 8.2 it states....

"The DHCP server submits a DNS query which deletes all of the PTR RRs
associated with the lease IP address, and adds a PTR RR whose data  is the
client's (possibly disambiguated) host name. The server also adds a DHCID
RR specified in Section 4.3."

It seems that the DHCID was created as a way to enforce a policy concerning
name collisions. As such, most of the discussion in the draft centers
around how the DHCID is used in performing A RR updates. Section 8.1
describes the prerequisite checking which takes place for A RR updates and
mentions the decision that must be made (based on an administrative policy)
as to whether an A RR should be updated if an existing A RR is found.
However, for PTR record updates, it simply states that the server adds the
DHCID RR (without any such pre-requisite checking and policy decisions).
Therefore, what is the purpose of adding a DHCID RR when adding a PTR
record?

Secondly, what is the status of DHCID? I have been unable to find reference
12 (draft-ietf-dnsext-dhcid-rr-*) mentioned in the DHCP-DNS interaction
draft. Does anyone know of any DNS servers that support a DHCID RR or if
they intend to support it in the future?

Thanks in advance for your responses!

Jack Corcoran
 Email: [email-masked]
 Ph  607-752-5570,  T/L 852-5570, FAX: 607-752-5421

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From: Bernie Volz <[email-masked]>
Date: Thu, 29 Jun 2000 10:28:17 -0400

Jack:

I believe the general concept is that the DHCP Server "owns" the address and
therefore it "knows" who is using the address and the name associated with
that address. That is why there is no need to check the DHCID information
(it perhaps even need not store DHCID, but it may be useful information for
administrators).

The name (A RR), on the other hand, is owned by ???. Thus, the checks there
have to be much more involved.

I can't answer the question regarding DHCID. Likely, it is waiting for this
draft to finalize?

- Bernie Volz
  IPWorks, Inc

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Tuesday, June 27, 2000 2:26 PM
To: DHCPv4 discussion list
Subject: Use of DHCID in draft-ietf-dhc-dhcp-dns-12

Jack Corcoran
 Email: [email-masked]

---

From: [email-masked]
Date: Fri, 30 Jun 2000 09:01:46 -0500

Thanks for the reply. I do understand the concept of who owns each record.
I just didn't see a purpose for the DHCID associated with the PTR, other
than as you suggested, it being a mechanism for an administrator to try and
tell who updated the record. Although, if it is "scrambled" via a hash
algorithm, I'm still not sure how useful it would be.

I guess I was just looking for a more definitive answer, like "oh that's
there because in the next version of the draft you'll see...." or "Yes you
are correct, and there really isn't a need for a DHCID record associated
with a PTR record."

Presently, since BIND8 DNS doesn't support DHCID (at least to my
knowledge), does anyone see a problem with using the KEY RR in place of the
DHCID which was the proposed method in a previous version of the subject
draft? At least that way a DHCP server capable of dynamic DNS updates could
be developed now that would interface to any BIND 8 DNS server.

Jack Corcoran
[email-masked]