[dnssd] Warren Kumari's No Objection on draft-ietf-dnssd-hybrid-07: (with COMMENT)
Warren Kumari <firstname.lastname@example.org> Tue, 28 November 2017 01:48 UTC
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From: Warren Kumari <email@example.com>
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Date: Mon, 27 Nov 2017 17:48:30 -0800
Subject: [dnssd] Warren Kumari's No Objection on draft-ietf-dnssd-hybrid-07: (with COMMENT)
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Warren Kumari has entered the following ballot position for draft-ietf-dnssd-hybrid-07: No Objection When responding, please keep the subject line intact and reply to all email addresses included in the To and CC lines. (Feel free to cut this introductory paragraph, however.) Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html for more information about IESG DISCUSS and COMMENT positions. The document, along with other ballot positions, can be found here: https://datatracker.ietf.org/doc/draft-ietf-dnssd-hybrid/ ---------------------------------------------------------------------- COMMENT: ---------------------------------------------------------------------- This was a DISCUSS, but I have changed to NoObj because I couldn't justify to myself which criteria covered it. I've changed to NoObj, but please address it... Original DISCUSS point: ---- This is (IMO) easily addressed -- I like the document, this DISCUSS is simply to improve it and help prevent foot-shooting. I'd be a YES or NoObj once addressed. There are a number of places where the non-LDH names may be configured on a "normal" DNS server. An example of this is in Section 5.2.1. Domain Enumeration via Unicast Queries: "db._dns-sd._udp.example.com. PTR Building 1.example.com." Putting this in a zonefile and trying to hand it to e.g BIND makes things sad: dns_rdata_fromtext: example.com:18: near '1.example.com.': extra input text zone example.com/IN: loading from master file example.com failed: extra input text zone example.com/IN: not loaded due to errors. Another example is in Section 5.3. Delegated Subdomain for LDH Host Names "For example, a Discovery Proxy could have the two subdomains "Building 1.example.com" and "bldg1.example.com" delegated to it." I think that the document needs to do a better job of explaining that you cannot just include non-LDH in a zonefile without escaping -- Section 5.1. (Format) of RFC1035 may be a good pointer. It may even be a good idea to repeat this (or at least mention the case) whenever there is an example - readers are likely to just cut and paste without reading the full document, leading to unexpected failures (and then gnashing of teeth on forums) ------ Please also see Joel's OpsDir review - it is relevant. Questions: Section 3 - Conventions and Terminology Used in this Document "A set of hosts is considered to be "on the same link" if: ..." I'd suggest "For the purposes of this document a set of hosts..." -- it feels a bit dangerous to be defining what being on a link is more globally, and this probably misses some corner cases and / or conflicts with some other definition. Section 5.1. Delegated Subdomain for Service Discovery Records "In the parent domain, NS records are used to delegate ownership of each defined link name (e.g., "Building 1.example.com")" - can you please provide a pointer here to (I think!) Section 5.5.4. No Text Encoding Translation? Section 5.2.1. Domain Enumeration via Unicast Queries "The "b" ("browse") records tell the client device the list of browsing domains to display for the user to select from and the "db" ("default browse") record tells the client device which domain in that list should be selected by default." What if b.[...] contains "foo" and "bar", and db.[...] contains "baz" (i.e the default browse is not in b)? Should "baz" be automagically added to b, or should it be ignored? The decision is likely implemented on the client, but I think worth noting here - I could see a lazy admin relying on the former and then later getting bitten if this changes. Section 5.4. Delegated Subdomain for Reverse Mapping "For example, in the "/usr/include/dns_sd.h" APIs (available on macOS, iOS, Bonjour for Windows, Linux and Android), ..." Is the API really at /usr/include/dns_sd.h" on Windows? (No idea, and I'm not inclined to go find a Windows box to test, but it sounded wrong so I flagged it!) Section 5.5.2. Suppressing Unusable Records I don't really understand the "MUST NOT" when a Proxy can determine if there are multiple address realms - I get why this is desirable, but if it is important enough to require a MUST NOT, then surely it should be a requirement that all proxies are able to do this (AFAICT, though manual config)? Also, if this is MUST NOT for v4, why is it only SHOULD NOT for v6 ULAs? (please educate me). Section 5.5.3. NSEC and NSEC3 queries "Since a Discovery Proxy only knows what names exist on the local link by issuing queries for them, ..." (specifically the "only") This may be a nit, but couldn't a DP also know that a name exists because a device advertised it? Nits: Section 5.2.2. Domain Enumeration via Multicast Queries "Since a Discovery Proxy exists on many, if not all, the links in an enterprise, it offers an additional way to provide Domain Enumeration data for clients." I think that this should be "many, if not all, *of* the links ..." -- but I'm not sure.
- [dnssd] Warren Kumari's No Objection on draft-iet… Warren Kumari