Talk:DNS zone

Rewrite of DNS query example

I've rewritten this to properly reflect how a DNS query actually occurs (AFAIK). In particular, no tokenisation occurs on the DNS resolver side; rather, each server is asked for the complete answer in turn. (Old version here.)

The incorrectness of the old version is made obvious if you try to apply the procedure to resolve "rr.pmtpa.wikimedia.org.". You would find yourself with an NXDOMAIN when you tried to look up nameservers for "pmtpa.wikimedia.org.", since the subdomain is not delegated out to other servers. (It could be delegated, though, so you can't assume it's not, either.) The correct approach was to ask for the complete address as early as posssible -- i.e. once at the root servers, once at the "org." servers, and once at the "wikimedia.org." servers, where you happen to get the final answer.

It also falls down if you ask for "wikipedia.org." rather than "en.wikipedia.org.", since without inside knowledge of how the hierarchy works, there's no way to know whether you're looking for a "wikipedia" host record served by the "org." nameserver, or a zone-root host record served by the "wikipedia.org." nameserver.

I considered keeping the old example and posting a big "note: this isn't how it really happens!" warning, but a rewrite (in prose form rather than bullet lists) seemed more appropriate. I'm still not really certain that a full DNS example belongs on this page, but in case it does, I figured it should at least be accurate. — Wisq (talk) 11:03, 17 April 2009 (UTC)

is defined by

"The DNS namespace is defined by RFC 1034, "Domain Names - Concepts and Facilities" and RFC 1035, "Domain Names - Implementation and Specification"", yes, but what is the actual definition? — Preceding unsigned comment added by 156.17.236.67 (talk) 22:15, 7 November 2011 (UTC)

In the definition "A DNS zone is a portion of a domain name space using the Domain Name System (DNS) for which administrative responsibility has been delegated," it is not clear by its location in the sentence whether the prepositional clause "for which administrative responsibility has been delegated" refers to (1) a DNS zone or (2) a domain name space using the Domain Name System or (3) the Domain Name System.

Also, it is not clear by its location in the sentence whether the prepositional phrase "using the Domain Name System (DNS)" refers to (1) a portion of a domain name space (2) a domain name space.

If you don't already know what a DNS zone is, before reading the sentence, the definition won't mean anything to you, because you can't tell which subject the clauses in question refer to, by their location in the sentence. Nomenclator (talk) 10:31, 17 March 2013 (UTC)

Forward DNS zones

The definition of a caching name server seems to be wrong here (the sentence says it doesn't answer from cache??). Also, I'm not sure if it's even called forward zone or if that section really belongs here:

„Another common use of the term forward zone refers to a specific configuration of DNS name servers, particularly caching name servers, in which resolution of a domain name is forwarded to another name server that is authoritative for the domain in question, rather than being answered from the established cache memory.”

In Microsoft DNS implementation you can set up conditional forwarding, in a sense it could be some kind of forward(ed) zone. SyP (talk) 18:41, 6 December 2011 (UTC)

The term "humanly-practical" is vague. The distinction between name-based domains and numerically identified internet resources is unclear. I might point out that when you describe something with a number that does not actually count or measure anything about the thing, but merely identifies it, than the number is being used as a name, rather than as a number. Thus ip addresses are not functioning as numbers, when they identifify a particular host; they are functioning as names.Nomenclator (talk) 10:39, 17 March 2013 (UTC)

RFCs

RFC 1034 first mentions the word ZONE in the sentence "Authoritative information is organized into units called ZONEs, and these zones can be automatically distributed to the name servers which provide redundant service for the data in a zone."

That wasn't much help. It starts using the word ZONE without defining it.

RFC 1035 isn't much help either. First use of the word ZONE: "Name servers manage two kinds of data. The first kind of data held in sets called zones; each zone is the complete database for a particular "pruned" subtree of the domain space. This data is called authoritative. A name server periodically checks to make sure that its zones are up to date, and if not, obtains a new copy of updated zones"

"The first kind of data held in sets called zones" is not even a sentence; there is no verb, just a subject and an object and no clue as to how they relate to each other. Then the second sentence (after the semi-colon") uses the word "pruned" without defining it, or what "called authoritative" means. RFC 1034 implies that the zone is the "information," or Data; RFC 1035 implies that a zone is the actual file ConTaining the data. Which is it? Not to be picky, but the clause "obtains a new copy of updated zones" contains a redundancy. A "NEW copy of UPDATED zone" tells us no more about what happens than a "COPY of UPDATED zone."Nomenclator (talk) 11:49, 18 March 2013 (UTC)

Problem sentence

Re the sentence "A DNS zone is a portion of a domain name space using the Domain Name System (DNS) for which administrative responsibility has been delegated" let me put the problem with that sentence this way: what is the name of the Domain Name System for which administrative responsibility has been delegated, and what is the name of the Domain Name System for which administrative responsibility has not been delegated? Why would a portion of a domain name space use a Domain Name System for which administrative responsibility has not been delegated? Nomenclator (talk) 14:26, 22 March 2013 (UTC)