Subject: Issues in DDNS-DHCP interaction drafts

From: Ralph Droms <[email-masked]>
Date: Thu, 05 Jun 2003 19:36:24 -0400

The following drafts have passed WG last call:

[1] A DNS RR for Encoding DHCP Information (DHCID RR)
    <draft-ietf-dnsext-dhcid-rr-06.txt> 

[2] The DHCP Client FQDN Option 
    <draft-ietf-dhc-fqdn-option-05.txt>

[3] Resolution of DNS Name Conflicts Among DHCP Clients 
    <draft-ietf-dhc-ddns-resolution-05.txt>

Several issues regarding these drafts have been identified
during the AD review prior to IESG review for Proposed
Standard status.  I will initiate discussion threads on
each of these issues later today with e-mail to both
the dhcwg and namedroppers mailing lists.  Please respond
just to the dhcwg mailing list to avoid duplicate postings...

- Ralph

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---

From: Mark Stapp <[email-masked]>
Date: Fri, 06 Jun 2003 15:28:59 -0400

Patrick,
Thanks for the comments. I'll fix the typo.

The ttl recommendations resulted from a couple of back-and-forths over a 
period of years, and the current set of numbers is based on recommendations 
from the dnsext wg chairs. The basic issue is that dns operators don't want 
stale rrs lying around after dhcp leases have expired, and at the same time 
they don't want micro-ttls that make caching ineffective. The core goal was 
to make implementors aware of the issue, and to recommend common sense when 
twiddling the configuration. The specific values were meant, I think, to be 
more concrete guidance, but not a substitute for good sense. As you 
observe, there's a recommendation, but the specifics are meant to be a 
guide, and that's why they're 'SHOULD'-strength. The '1/3' number is meant 
to address the 'stale rrs' concern, and the '10 minutes' is meant to 
address the 'micro-ttl' concern. Is there something else that could be said 
in section 5 that would make that clearer?

-- Mark

At 11:31 AM 6/6/2003 -0700, Cosmo, Patrick wrote:

>I have found some minor issues with the 
><draft-ietf-dhc-ddns-resolution-05.txt>, I apologize if they have already 
>been brought up.
>
>In particular, this statement in section 5. (DNS RR TTLs) on page 5:
>
>"The RR TTL on a DNS record added for with a DHCP lease SHOULD NOT exceed 
>1/3 of the lease time, and SHOULD be at least 10 minutes."
>
>1. This sentence has some bad grammar ("for with" : ... record added for 
>with a DHCP lease ...).
>
>2. The statement is contradictory if the lease time is less than 30 
>minutes. When the lease time is less than 30 minutes, which suggestion 
>takes precendence? : min. 10 minutes, or max or 1/3 lease time?
>
>3. The section seems intended to suggest a reasonable TTL for these 
>records, but doesn't seem to pull through or suggest much of anything 
>(IMHO) other than "it should be a function of lease time, and it should be 
>configurable".
>
>Patrick Cosmo
>
>Senior Product Engineer
>Incognito Software Inc
>Vancouver: (604) 688-4332 ext: 254
>Toll-Free: 1-800-877-1856
><http://www.incognito.com>http://www.incognito.com
>
>
>-----Original Message-----
>From: Ralph Droms [<mailto:[email-masked]>mailto:[email-masked]]
>Sent: Thursday, June 05, 2003 7:36 PM
>To: [email-masked]; [email-masked]
>Subject: [dhcwg] Issues in DDNS-DHCP interaction drafts
>
>_______________________________________________
>dhcwg mailing list
>[email-masked]
><https://www1.ietf.org/mailman/listinfo/dhcwg>https://www1.ietf.org/mailman/listinfo/dhcwg 
>

---

From: "Cosmo, Patrick" <[email-masked]>
Date: Fri, 6 Jun 2003 13:40:08 -0700

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>Is there something else that could be said 

Is the intention to recommend that the TTL time be 10 minutes or 1/3 of the
lease time, whichever is greater? If so:

"The RR TTL on a DNS record added for a DHCP lease SHOULD be 1/3 of the
lease time or 10 minutes, whichever is greater".

Or is the intention to recommend that any time between 10 minutes and 1/3 of
the lease time be used for TTL, except when 1/3 of the lease is less than 10
minutes, in which case the TTL should be 10 minutes? If so:

"The RR TTL on a DNS record added for a DHCP lease SHOULD NOT exceed 
1/3 of the lease time, unless 1/3 of the lease time amounts to less than 10
minutes. The RR TTL on a DNS record added for a DHCP lease SHOULD always be
at least 10 minutes."

-----Original Message-----
From: Mark Stapp [mailto:[email-masked]]
Sent: Friday, June 06, 2003 3:29 PM
To: Cosmo, Patrick
Cc: 'Ralph Droms'; [email-masked]; [email-masked]
Subject: RE: [dhcwg] Issues in DDNS-DHCP interaction drafts

Patrick,

-- Mark