>Is there something else that could be said
>in section 5 that would make that clearer?
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:mjs@cisco.com]
Sent: Friday, June 06, 2003 3:29 PM
To: Cosmo, Patrick
Cc: 'Ralph Droms'; dhcwg@ietf.org; namedroppers@ops.ietf.org
Subject: RE: [dhcwg] Issues in DDNS-DHCP interaction drafts
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:rdroms@cisco.com>mailto:rdroms@cisco.com]
>Sent: Thursday, June 05, 2003 7:36 PM
>To: dhcwg@ietf.org; namedroppers@ops.ietf.org
>Subject: [dhcwg] Issues in DDNS-DHCP interaction drafts
>
>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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>