Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-terminals
Edward Lewis <Ed.Lewis@neustar.biz> Wed, 30 March 2011 20:25 UTC
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Date: Wed, 30 Mar 2011 16:27:14 -0400
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From: Edward Lewis <Ed.Lewis@neustar.biz>
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Subject: Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-terminals
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At 12:04 +0000 3/30/11, Florian Weimer wrote: >> >> http://tools.ietf.org/html/draft-vixie-dnsext-resimprove-00 > >I was referring to section 3. I think it is misleading and would lead >to poorer service from resolvers if implemented. Florian, thanks for the pointer. I really had lost track of the thread. In section 3, it mentions an ambiguity in RFC 1034. Question: what ambiguity (there are a lot of them), like what section or page. I'm asking out of curiosity. Still, the point of section 3 is right. If there were no bad code out there and if the data never changed then I'd say it is good. But there is bad code out there. Dan Bernstein's statement (as found in [0]) that returning NXDOMAIN for empty non-terminals is acceptable because buggy code did this in the past is an interesting point. While technically wrong to do so, this code is out there and to accommodate (work around the bug), optimizing according what is in section 3 would be sub-optimal. I would never say that NXDOMAIN for empty non-terminals is correct as a protocol analyst. But if I was dealing with buggy code, I'd play the "be liberal in what you accept" card. Secondly, because of the fact that things change, it might be wrong for a cache to synthesize, based on a cached NXDOMAIN what may now be in a subdomain of the zone authoritative for the NXDOMAIN. To me, this is a secondary concern because we've long recognized that the DNS protocol is pretty much agnostic about time. It is true that RFC's in the past have said an NXDOMAIN can be used by caches to declare data of any type at a name as non-existing - but this pertains to the same name, not descendents. So, while I think in theory section 3 is correct, in practice it seems to be an over-optimization given an imperfect world. [0] - http://www.ietf.org/mail-archive/web/dnsext/current/msg11084.html (I don't see a message "directly" from him, just this forward. In case the forward was a forgery my point is directed at the real source of the comment, not Dan Bernstein.) -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Edward Lewis NeuStar You can leave a voice message at +1-571-434-5468 Me to infant son: "Waah! Waah! Is that all you can say? Waah?" Son: "Waah!"
- [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-term… Colm MacCárthaigh
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Matthew Dempsky
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Colm MacCárthaigh
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- [dnsext] list-meta: moderation (was: Fwd: djb on … Andrew Sullivan
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Florian Weimer
- Re: [dnsext] list-meta: moderation (was: Fwd: djb… Phillip Hallam-Baker
- Re: [dnsext] list-meta: moderation (was: Fwd: djb… Andrew Sullivan
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Tony Finch
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Florian Weimer
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Edward Lewis
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Edward Lewis
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Edward Lewis
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Florian Weimer
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Edward Lewis
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Paul Vixie
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Colm MacCárthaigh
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Sabahattin Gucukoglu
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Edward Lewis
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Tony Finch
- Re: [dnsext] Fwd: djb on NXDOMAIN/NODATA for non-… Edward Lewis