Re: [DNSOP] Where in a CNAME chain is the QNAME?
Robert Edmonds <edmonds@mycre.ws> Mon, 26 September 2016 16:48 UTC
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Date: Mon, 26 Sep 2016 12:48:19 -0400
From: Robert Edmonds <edmonds@mycre.ws>
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References: <20160920161350.GA3288@laperouse.bortzmeyer.org> <20160923082232.6j2jlr4wqp2fxs56@nic.fr> <7F671C9C-BEEC-479B-99FB-8618C3C75526@powerdns.com> <8A664A35-806C-4F8C-B836-B2A1438FAEA6@vpnc.org>
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Subject: Re: [DNSOP] Where in a CNAME chain is the QNAME?
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Paul Hoffman wrote: > On 26 Sep 2016, at 0:33, Peter van Dijk wrote: > > > 2308 does not “redefine” QNAME. It clarifies that the usage in 1034 > > 4.3.2 is the definition we use in RFCs. 1035 4.1(.2) does not conflict > > with this; the QNAME there is just the initial QNAME. > > This seems like a very limited view of RFC 1034. RFC 1034 actually defines > QNAME in Section 3.7.1: > > 3.7.1. Standard queries > > A standard query specifies a target domain name (QNAME), query type > (QTYPE), and query class (QCLASS) and asks for RRs which match. > > Further, the usage in Section 4.3.2 does not say that the QNAME is the last > name in the chain, just that the algorithm itself repeats with a new value > for QNAME: > > If the data at the node is a CNAME, and QTYPE doesn't > match CNAME, copy the CNAME RR into the answer section > of the response, change QNAME to the canonical name in > the CNAME RR, and go back to step 1. If STD 13 were to be typeset like a technical book, "QNAME" in 1034 §4.3.2 would be styled using the book's typographical convention for a variable name. The exact same formulation in §4.3 ("change … to the canonical name in the CNAME RR") is used again in the resolver algorithm in §5.3: The following resolver algorithm assumes that all functions have been converted to a general lookup function, and uses the following data structures to represent the state of a request in progress in the resolver: SNAME the domain name we are searching for. STYPE the QTYPE of the search request. SCLASS the QCLASS of the search request. […] 5.3.3. Algorithm The top level algorithm has four steps: […] 4. Analyze the response, either: […] c. if the response shows a CNAME and that is not the answer itself, cache the CNAME, change the SNAME to the canonical name in the CNAME RR and go to step 1. […] Since "SNAME" doesn't conflict with a term from another part of the document set, it's clear that SNAME is being used as a variable name. So the parallel use in §4.3.2 ("change QNAME to the canonical name") must also be as a variable name, not a terminological (re)definition. -- Robert Edmonds
- [DNSOP] Where in a CNAME chain is the QNAME? Stephane Bortzmeyer
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Robert Edmonds
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Paul Hoffman
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Warren Kumari
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Peter van Dijk
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Peter van Dijk
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Stephane Bortzmeyer
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Viktor Dukhovni
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Robert Edmonds
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Stephane Bortzmeyer
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Peter van Dijk
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Ólafur Guðmundsson
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Matt Larson
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Paul Hoffman
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Robert Edmonds
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Peter van Dijk
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Suzanne Woolf
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Stephane Bortzmeyer
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Stephane Bortzmeyer
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Robert Edmonds
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Viktor Dukhovni
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Shumon Huque
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Stephane Bortzmeyer
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Paul Hoffman
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Shumon Huque
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Paul Hoffman
- Re: [DNSOP] Where in a CNAME chain is the QNAME? Robert Edmonds