📄 rfc1034.4up.ps
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%Page: (5) 5%BeginPageSetup_S% N-up sub-page 1/40 -392 translate0.490859 dup scale/pagenum 5 def/fname (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/rfc1034.txt) def/fdir (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/) def/ftail (rfc1034.txt) def% User defined strings:/fmodstr (Tue Nov 24 00:00:00 1987) def/pagenumstr (5) def/user_header_p true def/user_header_left_str (RFC1034) def/user_header_center_str (RFC.net) def/user_header_right_str (Page 5 of 56) def%%EndPageSetupdo_header5 751 M(RFC 1034 Domain Concepts and Facilities November 1987) s5 712 M(The domain system assumes that all data originates in master files) s5 699 M(scattered through the hosts that use the domain system. These master) s5 686 M(files are updated by local system administrators. Master files are text) s5 673 M(files that are read by a local name server, and hence become available) s5 660 M(through the name servers to users of the domain system. The user) s5 647 M(programs access name servers through standard programs called resolvers.) s5 621 M(The standard format of master files allows them to be exchanged between) s5 608 M(hosts \(via FTP, mail, or some other mechanism\); this facility is useful) s5 595 M(when an organization wants a domain, but doesn't want to support a name) s5 582 M(server. The organization can maintain the master files locally using a) s5 569 M(text editor, transfer them to a foreign host which runs a name server,) s5 556 M(and then arrange with the system administrator of the name server to get) s5 543 M(the files loaded.) s5 517 M(Each host's name servers and resolvers are configured by a local system) s5 504 M(administrator [RFC-1033]. For a name server, this configuration data) s5 491 M(includes the identity of local master files and instructions on which) s5 478 M(non-local master files are to be loaded from foreign servers. The name) s5 465 M(server uses the master files or copies to load its zones. For) s5 452 M(resolvers, the configuration data identifies the name servers which) s5 439 M(should be the primary sources of information.) s5 413 M(The domain system defines procedures for accessing the data and for) s5 400 M(referrals to other name servers. The domain system also defines) s5 387 M(procedures for caching retrieved data and for periodic refreshing of) s5 374 M(data defined by the system administrator.) s5 348 M(The system administrators provide:) s5 322 M( - The definition of zone boundaries.) s5 296 M( - Master files of data.) s5 270 M( - Updates to master files.) s5 244 M( - Statements of the refresh policies desired.) s5 218 M(The domain system provides:) s5 192 M( - Standard formats for resource data.) s5 166 M( - Standard methods for querying the database.) s5 140 M( - Standard methods for name servers to refresh local data from) s5 127 M( foreign name servers.) s5 49 M(Mockapetris [Page 5]) s_R%Page: (6) 6%BeginPageSetup_S% N-up sub-page 2/4278 -392 translate0.490859 dup scale/pagenum 6 def/fname (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/rfc1034.txt) def/fdir (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/) def/ftail (rfc1034.txt) def% User defined strings:/fmodstr (Tue Nov 24 00:00:00 1987) def/pagenumstr (6) def/user_header_p true def/user_header_left_str (RFC1034) def/user_header_center_str (RFC.net) def/user_header_right_str (Page 6 of 56) def%%EndPageSetupdo_header5 751 M(RFC 1034 Domain Concepts and Facilities November 1987) s5 712 M(2.4. Elements of the DNS) s5 686 M(The DNS has three major components:) s5 660 M( - The DOMAIN NAME SPACE and RESOURCE RECORDS, which are) s5 647 M( specifications for a tree structured name space and data) s5 634 M( associated with the names. Conceptually, each node and leaf) s5 621 M( of the domain name space tree names a set of information, and) s5 608 M( query operations are attempts to extract specific types of) s5 595 M( information from a particular set. A query names the domain) s5 582 M( name of interest and describes the type of resource) s5 569 M( information that is desired. For example, the Internet) s5 556 M( uses some of its domain names to identify hosts; queries for) s5 543 M( address resources return Internet host addresses.) s5 517 M( - NAME SERVERS are server programs which hold information about) s5 504 M( the domain tree's structure and set information. A name) s5 491 M( server may cache structure or set information about any part) s5 478 M( of the domain tree, but in general a particular name server) s5 465 M( has complete information about a subset of the domain space,) s5 452 M( and pointers to other name servers that can be used to lead to) s5 439 M( information from any part of the domain tree. Name servers) s5 426 M( know the parts of the domain tree for which they have complete) s5 413 M( information; a name server is said to be an AUTHORITY for) s5 400 M( these parts of the name space. Authoritative information is) s5 387 M( organized into units called ZONEs, and these zones can be) s5 374 M( automatically distributed to the name servers which provide) s5 361 M( redundant service for the data in a zone.) s5 335 M( - RESOLVERS are programs that extract information from name) s5 322 M( servers in response to client requests. Resolvers must be) s5 309 M( able to access at least one name server and use that name) s5 296 M( server's information to answer a query directly, or pursue the) s5 283 M( query using referrals to other name servers. A resolver will) s5 270 M( typically be a system routine that is directly accessible to) s5 257 M( user programs; hence no protocol is necessary between the) s5 244 M( resolver and the user program.) s5 218 M(These three components roughly correspond to the three layers or views) s5 205 M(of the domain system:) s5 179 M( - From the user's point of view, the domain system is accessed) s5 166 M( through a simple procedure or OS call to a local resolver.) s5 153 M( The domain space consists of a single tree and the user can) s5 140 M( request information from any section of the tree.) s5 114 M( - From the resolver's point of view, the domain system is) s5 101 M( composed of an unknown number of name servers. Each name) s5 49 M(Mockapetris [Page 6]) s_R%Page: (7) 7%BeginPageSetup_S% N-up sub-page 3/40 -794 translate0.490859 dup scale/pagenum 7 def/fname (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/rfc1034.txt) def/fdir (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/) def/ftail (rfc1034.txt) def% User defined strings:/fmodstr (Tue Nov 24 00:00:00 1987) def/pagenumstr (7) def/user_header_p true def/user_header_left_str (RFC1034) def/user_header_center_str (RFC.net) def/user_header_right_str (Page 7 of 56) def%%EndPageSetupdo_header5 751 M(RFC 1034 Domain Concepts and Facilities November 1987) s5 712 M( server has one or more pieces of the whole domain tree's data,) s5 699 M( but the resolver views each of these databases as essentially) s5 686 M( static.) s5 660 M( - From a name server's point of view, the domain system consists) s5 647 M( of separate sets of local information called zones. The name) s5 634 M( server has local copies of some of the zones. The name server) s5 621 M( must periodically refresh its zones from master copies in) s5 608 M( local files or foreign name servers. The name server must) s5 595 M( concurrently process queries that arrive from resolvers.) s5 569 M(In the interests of performance, implementations may couple these) s5 556 M(functions. For example, a resolver on the same machine as a name server) s5 543 M(might share a database consisting of the the zones managed by the name) s5 530 M(server and the cache managed by the resolver.) s5 504 M(3. DOMAIN NAME SPACE and RESOURCE RECORDS) s5 478 M(3.1. Name space specifications and terminology) s5 452 M(The domain name space is a tree structure. Each node and leaf on the) s5 439 M(tree corresponds to a resource set \(which may be empty\). The domain) s5 426 M(system makes no distinctions between the uses of the interior nodes and) s5 413 M(leaves, and this memo uses the term "node" to refer to both.) s5 387 M(Each node has a label, which is zero to 63 octets in length. Brother) s5 374 M(nodes may not have the same label, although the same label can be used) s5 361 M(for nodes which are not brothers. One label is reserved, and that is) s5 348 M(the null \(i.e., zero length\) label used for the root.) s5 322 M(The domain name of a node is the list of the labels on the path from the) s5 309 M(node to the root of the tree. By convention, the labels that compose a) s5 296 M(domain name are printed or read left to right, from the most specific) s5 283 M(\(lowest, farthest from the root\) to the least specific \(highest, closest) s5 270 M(to the root\).) s5 244 M(Internally, programs that manipulate domain names should represent them) s5 231 M(as sequences of labels, where each label is a length octet followed by) s5 218 M(an octet string. Because all domain names end at the root, which has a) s5 205 M(null string for a label, these internal representations can use a length) s5 192 M(byte of zero to terminate a domain name.) s5 166 M(By convention, domain names can be stored with arbitrary case, but) s5 153 M(domain name comparisons for all present domain functions are done in a) s5 140 M(case-insensitive manner, assuming an ASCII character set, and a high) s5 127 M(order zero bit. This means that you are free to create a node with) s5 114 M(label "A" or a node with label "a", but not both as brothers; you could) s5 101 M(refer to either using "a" or "A". When you receive a domain name or) s5 49 M(Mockapetris [Page 7]) s_R%Page: (8) 8%BeginPageSetup_S% N-up sub-page 4/4278 -794 translate0.490859 dup scale/pagenum 8 def/fname (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/rfc1034.txt) def/fdir (/usr/local/share/doc/rfc/Mirrors/ftp.isi.edu/in-notes/) def/ftail (rfc1034.txt) def% User defined strings:/fmodstr (Tue Nov 24 00:00:00 1987) def/pagenumstr (8) def/user_header_p true def/user_header_left_str (RFC1034) def/user_header_center_str (RFC.net) def/user_header_right_str (Page 8 of 56) def%%EndPageSetupdo_header5 751 M(RFC 1034 Domain Concepts and Facilities November 1987) s5 712 M(label, you should preserve its case. The rationale for this choice is) s5 699 M(that we may someday need to add full binary domain names for new) s5 686 M(services; existing services would not be changed.) s5 660 M(When a user needs to type a domain name, the length of each label is) s5 647 M(omitted and the labels are separated by dots \("."\). Since a complete) s5 634 M(domain name ends with the root label, this leads to a printed form which) s5 621 M(ends in a dot. We use this property to distinguish between:) s5 595 M( - a character string which represents a complete domain name) s5 582 M( \(often called "absolute"\). For example, "poneria.ISI.EDU.") s5 556 M( - a character string that represents the starting labels of a) s5 543 M( domain name which is incomplete, and should be completed by) s5 530 M( local software using knowledge of the local domain \(often) s5 517 M( called "relative"\). For example, "poneria" used in the) s5 504 M( ISI.EDU domain.) s5 478 M(Relative names are either taken relative to a well known origin, or to a) s5 465 M(list of domains used as a search list. Relative names appear mostly at) s5 452 M(the user interface, where their interpretation varies from) s5 439 M(implementation to implementation, and in master files, where they are) s5 426 M(relative to a single origin domain name. The most common interpretation) s5 413 M(uses the root "." as either the single origin or as one of the members) s5 400 M(of the search list, so a multi-label relative name is often one where) s5 387 M(the trailing dot has been omitted to save typing.) s5 361 M(To simplify implementations, the total number of octets that represent a) s5 348 M(domain name \(i.e., the sum of all label octets and label lengths\) is) s5 335 M(limited to 255.) s5 309 M(A domain is identified by a domain name, and consists of that part of) s5 296 M(the domain name space that is at or below the domain name which) s5 283 M(specifies the domain. A domain is a subdomain of another domain if it) s5 270 M(is contained within that domain. This relationship can be tested by) s5 257 M(seeing if the subdomain's name ends with the containing domain's name.) s5 244 M(For example, A.B.C.D is a subdomain of B.C.D, C.D, D, and " ".) s5 218 M(3.2. Administrative guidelines on use) s5 192 M(As a matter of policy, the DNS technical specifications do not mandate a) s5 179 M(particular tree structure or rules for selecting labels; its goal is to) s5 166 M(be as general as possible, so that it can be used to build arbitrary) s5 153 M(applications. In particular, the system was designed so that the name) s5 140 M(space did not have to be organized along the lines of network) s5 127 M(boundaries, name servers, etc. The rationale for this is not that the) s5 114 M(name space should have no implied semantics, but rather that the choice) s5 101 M(of implied semantics should be left open to be used for the problem at) s5 49 M(Mockapetris [Page 8]) s_R_R⌨️ 快捷键说明
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