Re: [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot on key lengths...)
Mark Andrews <marka@isc.org> Wed, 02 April 2014 03:24 UTC
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To: Andrew Sullivan <ajs@anvilwalrusden.com>
From: Mark Andrews <marka@isc.org>
References: <0EA28BE8-E872-46BA-85FD-7333A1E13172@icsi.berkeley.edu> <53345C77.8040603@uni-due.de> <B7893984-2FAD-472D-9A4E-766A5C212132@pch.net> <102C13BE-E45E-437A-A592-FA373FF5C8F0@ogud.com> <474B0834-C16B-4843-AA0A-FC2A2085FEFB@icsi.berkeley.edu> <CAMm+Lwh-G7D5Cjx4NWMOhTjBZd=VVRHiPdK7L1zm-P0QRP8P2Q@mail.gmail.com> <20140401223943.528B71226903@rock.dv.isc.org> <20140402025854.GB90415@mx1.yitter.info>
In-reply-to: Your message of "Tue, 01 Apr 2014 22:58:54 -0400." <20140402025854.GB90415@mx1.yitter.info>
Date: Wed, 02 Apr 2014 14:23:50 +1100
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Subject: Re: [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot on key lengths...)
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In message <20140402025854.GB90415@mx1.yitter.info>, Andrew Sullivan writes: > On Wed, Apr 02, 2014 at 09:39:43AM +1100, Mark Andrews wrote: > > > Always set CD=1 is also bad advice. Stub resolvers need to send > > both CD=1 and CD=0 queries and should default to CD=0. CD=1 should > > be left to the case where they get a SERVFAIL result to the CD=0 > > to handle the case where the recursive server's clock is broken or > > it has a bad trust anchor. > > It strikes me that this argument has been hashed pretty well to death > before, but just to refresh everyone's memory, there are several > different strategies one can use here: > > 1. CD=1 all the time, and if you get into trouble consider the > failure a feature. Mark's argument (which has some merit) is that > this is too strong, because if the stub gets the bogus answer, it > can't "fall through" and pick up another one that might be good. > > 2. CD=1 mostly, and if you get a failure try falling back to CD=0. > Maybe with CD=0, the recursive server will find you something that > validates in order to get you on your way. > > 3. The opposite of (2), defauling to CD=0 (what Mark advocates). > > 4. Give up on stubs and be a full service resolver all the time. > > For 1-3, people may have a peek at RFC 6840, especially section 5.9 > and Appendix B. And I pointed out before RFC 6840 was published that the appendix was incomplete in its analysis. You didn't want to reopen the analysis, as it was a long discussion to get what was there, and the wg, I suspect, was too fried to care one way or the other. As a result we have to deal with the fallout now. > None of this, AFAICT, helps us at all with the 1024/2048 choice. Actually it does as it shows that recursive servers need to validate. If you are looking at workload you have to factor that into the analysis. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org
- [DNSOP] Whiskey Tango Foxtrot on key lengths... Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Hoffman
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Rose, Scott
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Stephane Bortzmeyer
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Matthäus Wander
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Christopher Morrow
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Christopher Morrow
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Wouters
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Wouters
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Bill Woodcock
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Tony Finch
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Andrew Sullivan
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Tony Finch
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Thierry Moreau
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Matthäus Wander
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Joe Abley
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… S Moonesamy
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Bill Woodcock
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Jelte Jansen
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Mark Andrews
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Mark Andrews
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Hoffman
- [DNSOP] CD (Re: Whiskey Tango Foxtrot on key leng… Evan Hunt
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Mark Andrews
- [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot on … Andrew Sullivan
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Olafur Gudmundsson
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Colm MacCárthaigh
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Wouters
- Re: [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot… Mark Andrews
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Nicholas Weaver
- Re: [DNSOP] CD bit (was Re: Whiskey Tango Foxtrot… Andrew Sullivan
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Colm MacCárthaigh
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Phillip Hallam-Baker
- [DNSOP] Current DNSOP thread and why 1024 bits Edward Lewis
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Nicholas Weaver
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Stephane Bortzmeyer
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Paul Hoffman
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Hoffman
- [DNSOP] mailing list behavior Re: Current DNSOP t… Suzanne Woolf
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Colm MacCárthaigh
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Wouters
- Re: [DNSOP] Current DNSOP thread and why 1024 bits S Moonesamy
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Hoffman
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Rose, Scott
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Mark Andrews
- Re: [DNSOP] CD (Re: Whiskey Tango Foxtrot on key … Colm MacCárthaigh
- Re: [DNSOP] Current DNSOP thread and why 1024 bits S Moonesamy
- Re: [DNSOP] Current DNSOP thread and why 1024 bits David Conrad
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Paul Wouters
- Re: [DNSOP] Current DNSOP thread and why 1024 bits Ben Laurie
- Re: [DNSOP] Whiskey Tango Foxtrot on key lengths.… Francis Dupont