[BACK]Return to adr-1 CVS log [TXT] [DIR] Up to [Research Unix] / researchv10dc / doc / csnet

Annotation of researchv10dc/doc/csnet/adr-1, revision 1.1

1.1     ! root        1: From research!mtune!rutgers!SH.CS.NET!cic Wed Sep 30 00:55:41 1987
        !             2: Received: by mtune.ATT.COM (smail2.5)
        !             3:        id AA19906; 30 Sep 87 00:55:41 EDT (Wed)
        !             4: Received: by RUTGERS.EDU (5.54/1.14) 
        !             5:        id AA19128; Tue, 29 Sep 87 18:14:44 EDT
        !             6: Message-Id: <[email protected]>
        !             7: Received: by SH.CS.NET id ac10308; 29 Sep 87 15:25 EDT
        !             8: Date: Tue, 29 Sep 87 14:24:40 EDT
        !             9: Subject: adr-1 CSNET ADDRESSES
        !            10: Reply-To: rutgers!SH.CS.NET!cic
        !            11: From: CSNET INFO SERVER <rutgers!SH.CS.NET!info>
        !            12: To: [email protected]
        !            13: 
        !            14: Request: info
        !            15: Topic: adr-1
        !            16: Document Updated:  1 Jun 87
        !            17: Subject: CSNET Addresses and the Domain System
        !            18: ==============================================================================
        !            19: CSNET Coordination and Information Center (CIC)         Hotline: 617/497-2777
        !            20: 10 Moulton Street                                        Email:  [email protected]
        !            21: Cambridge, MA 02238             Info-Server requests to: [email protected]
        !            22: ==============================================================================
        !            23: 
        !            24:                    CSNET ADDRESSES AND THE DOMAIN SYSTEM
        !            25: 
        !            26: In July 1986, the CSNET CIC instituted a new policy of assigning a
        !            27: domain-style name to each new CSNET PhoneNet site before the site begins
        !            28: to send messages on PhoneNet.  This starts the site off right, with a
        !            29: name that conforms to the DDN Domain Naming System , and avoids the pain
        !            30: of changing names in the future.
        !            31: 
        !            32: Assigning a domain name involves registering a second-level domain name
        !            33: with the Network Information Center (NIC) of the Defense Data Network
        !            34: (DDN).  The CSNET CIC has arranged with the DDN NIC to take care of the
        !            35: registration process for organizations that are members of the CSNET
        !            36: PhoneNet.  In a companion document, "adr-2  Transition to Domains", 
        !            37: CSNET-FORUM v2 #6 (23 May 86), we explained how to choose a domain name
        !            38: and register with the NIC.  In this article, we talk about the
        !            39: background of the domain naming system.
        !            40: 
        !            41: The DDN is composed of the ARPANET, an experimental research and
        !            42: development network, and the MILNET, an operational military network.
        !            43: The Internet is composed of the DDN, plus other networks that share the
        !            44: same protocols, including the CSNET X25Net.  CSNET PhoneNet sites are
        !            45: not part of the Internet, but they can exchange electronic messages with
        !            46: the Internet through a "gateway" on RELAY.CS.NET (also known as
        !            47: CSNET-RELAY.ARPA).  This is the same host that also connects PhoneNet
        !            48: sites to each other, and to other networks, public and private, that
        !            49: have gateways on CSNET PhoneNet sites.
        !            50: 
        !            51: The domain naming scheme represents an important step in making all
        !            52: these networks easier to use and allowing them to expand in the future.
        !            53: 
        !            54: In the past, the addressing scheme used by the DDN was based upon
        !            55: individual host computers.  As spelled out in RFC733 (the ARPANET
        !            56: standard for text messages adopted in 1977), and in earlier standards,
        !            57: the basic pattern for an ARPANET address was:
        !            58: 
        !            59:                        user@host
        !            60: 
        !            61: On the ARPANET, the hostnames must be translated into network numbers
        !            62: before the mail delivery programs can make connections between hosts.
        !            63: The original system stored the machine addresses with the host names in
        !            64: a host table.  The NIC Host Table was distributed by the DDN NIC to all
        !            65: hosts on the network.
        !            66: 
        !            67: The RFC733 system was firmly based on hardware.  If a single
        !            68: organization had multiple host computers on the ARPANET, all of the
        !            69: hosts had to be registered with the Network Information Center of the
        !            70: DDN (NIC) and entered in the NIC Host Table.  But if there were hosts
        !            71: that were not on the ARPANET themselves, but could be reached through an
        !            72: ARPANET host, the NIC Host Table could not handle them.  It was up to
        !            73: the person sending the messages to spell out the route explicitly in the
        !            74: mailing address.  
        !            75: 
        !            76: RFC733 did not, however, specify the rules for addressing messages to
        !            77: hosts on other networks.  The address form 'user%host1@host2', was
        !            78: generally used on the CSNET PhoneNet and other networks associated with
        !            79: the ARPANET, but was never adopted as a network standard, although the
        !            80: current network standard allows it (as one of many possible options). Some
        !            81: networks that gatewayed to the ARPANET used somewhat different rules,
        !            82: which were also acceptable.
        !            83: 
        !            84: The new domain system is quite different.  It is based on RFC822, which
        !            85: was adopted in 1983.  RFC822 specifies a system of names, not physical
        !            86: addresses.  It sets up a domain, corresponding to an organizational
        !            87: unit, not the physical hardware, as the basic unit of the name.  All
        !            88: users at the same organization have addresses in the same domain,
        !            89: regardless of the hardware they use or the network or route that
        !            90: delivers their messages.
        !            91: 
        !            92: This means that only one name, the domain name for the organization,
        !            93: must be registered with the NIC.  Names below the level of the
        !            94: organization as a whole are left up to the organizations to manage.  The
        !            95: responsibility for keeping track of the names and locations of host
        !            96: computers is thus delegated, and information is no longer centralized at
        !            97: the DDN NIC.  Eventually, when the domain system is fully implemented,
        !            98: the NIC will discontinue the NIC Host Table altogether.
        !            99: 
        !           100: Distributed responsibility for names requires a distributed database.
        !           101: Domain names must still be translated into network numbers and routes
        !           102: between hosts, but this information is no longer kept in one place.
        !           103: Instead, it is split up and stored on different Internet host computers
        !           104: in dynamic database programs called "domain servers".  When an Internet
        !           105: host is about to send a message, it no longer checks its own copy of the
        !           106: NIC Host Table for the recipient host.  Instead, it queries other
        !           107: Internet hosts, over real-time connections, to determine which Internet
        !           108: host runs the domain server that stores the routing information for the
        !           109: recipient's domain.  The sending host then retrieves the routing
        !           110: information, and routes the message to its destination (or at least to
        !           111: the next Internet host along its route).
        !           112: 
        !           113: CSNET PhoneNet sites cannot run their own domain servers, since they do
        !           114: not have direct real-time access to the Internet; instead, they must
        !           115: arrange with other hosts that are on the Internet to perform this
        !           116: function.  The CSNET CIC runs a domain server on RELAY.CS.NET, with a
        !           117: backup on SH.CS.NET, and offers to be the domain server for any PhoneNet
        !           118: site that needs this service.  
        !           119: 
        !           120: Domain names are organized in a hierarchical tree structure.  At the top
        !           121: is a set of top-level domain names chosen and administered by the DDN
        !           122: NIC.  The top-level domains for the United States represent classes of
        !           123: organizations:
        !           124: 
        !           125:     COM  Commercial organizations     MIL  Department of Defense
        !           126:     EDU  Educational organizations    NET  Administrative organizations 
        !           127:     GOV  Civilian government               for networks, e.g., CSNET.
        !           128:     ORG  Nonprofit organizations      ARPA Temporary top-level domain, 
        !           129: 
        !           130: Non-US countries have their own top-level domains, named for the
        !           131: 2-letter country codes of the International Standards Organization
        !           132: (ISO standard 3166).  The DDN NIC has announces country domains, as they
        !           133: are registered. 
        !           134: 
        !           135: Second-level domains represent individual organizations.  Hypothetical
        !           136: examples of domains for organizations might be:
        !           137: 
        !           138:             OXBRIDGE.EDU            Oxbridge University
        !           139:            WIDGETS.COM             Widgets Mfg. Co., Inc.
        !           140:            THINKTANK.ORG           The Thinktank Institute
        !           141: 
        !           142: Each new CSNET organization forms its domain name by selecting the
        !           143: appropriate top-level domain, and choosing a second-level domain.  The
        !           144: CSNET CIC checks the combination to make sure that it is unique.
        !           145: 
        !           146: Once an organization has been registered as a second-level domain, it
        !           147: may freely create lower-level domains, according to its needs.
        !           148: 
        !           149: The pattern for an electronic mail address is:
        !           150: 
        !           151:                         local-part@domain             
        !           152: 
        !           153: The "local-part" is ideally a simple username, but RFC822 allows any
        !           154: string in the local part (to the left of the @), so long as it can be
        !           155: interpreted by the machine that takes the responsibility for
        !           156: interpreting the complete "domain" (to the right of the @).
        !           157: 
        !           158: The domain is a string of words separated by periods.  Lower-level
        !           159: domains are arranged left to right, in ascending order, ending with a
        !           160: top-level domain.  Any number of lower-level domains may be used.
        !           161: 
        !           162: A domain may represent a subdivision of an organization (at any level),
        !           163: or an individual host computer.
        !           164: 
        !           165: Examples of addresses might be:
        !           166: 
        !           167:     [email protected]           oxbridge.edu either has no subdomains, 
        !           168:                                  or hides its subdomains from the 
        !           169:                                   outside world.
        !           170:     [email protected]       Engineering Dept within oxbridge.edu.
        !           171:     [email protected]    AI project in the Computer Science 
        !           172:                                   Department
        !           173:     [email protected]  Workstation in the Campus Computer 
        !           174:                                   Center.
        !           175: 
        !           176: The transition to domains is not yet complete.  Some Internet hosts are
        !           177: not yet running domain servers, and some have not yet made the switch
        !           178: from the temporary ".arpa" domain to the full domain naming scheme.  
        !           179: 
        !           180: The CSNET relay, originally CSNET-RELAY, then CSNET-RELAY.ARPA, and now
        !           181: RELAY.CS.NET, rewrites all CSNET PhoneNet addresses to include the
        !           182: relay's name when the message is destined for the Internet:
        !           183: 
        !           184:        From: @RELAY.CS.NET:[email protected]
        !           185: 
        !           186: Later, when all Internet hosts have domain servers, and are able to
        !           187: recognize all domain names, whether or not they are on the Internet,
        !           188: the address will change to:
        !           189: 
        !           190:        From: [email protected]
        !           191: 
        !           192: 
        !           193: THE RFC822 ROUTING ADDRESS
        !           194: 
        !           195:     For a long time, even after the RFC822 conventions were formally
        !           196: adopted for use on the Internet, the most common method of writing the
        !           197: routing address was the "%" notation:
        !           198: 
        !           199:        user%[email protected]
        !           200: 
        !           201:     However, this type of routing address is an informal convention,
        !           202: and is not specified in any official RFC or other Internet document.
        !           203: The routing address specified in RFC822 is of the form:
        !           204: 
        !           205:        @relay.cs.net:[email protected]
        !           206: 
        !           207:     This is the form that relay.cs.net uses for messages that are sent
        !           208: from CSNET PhoneNet sites to Internet hosts.
        !           209: 
        !           210:     You will also see routing addresses for CSNET PhoneNet sites with
        !           211: domain-style names.  The reason is that there are still some Internet
        !           212: hosts that cannot handle domain server entries for off-Internet hosts.
        !           213: 
        !           214:        @relay.cs.net:[email protected]
        !           215: 
        !           216: Other examples of RFC822 routing addresses are:
        !           217: 
        !           218:        @wiscvm.wisc.edu:[email protected]
        !           219:        @seismo.css.gov:[email protected] 
        !           220: 
        !           221: It is possible for a routing address to route through multiple hosts:
        !           222: 
        !           223:        @elsewhere.com,@nowhere.edu,@relay.cs.net:[email protected]
        !           224: 
        !           225: REFERENCES (Available from the CSNET Info Server):
        !           226: 
        !           227: RFC733 "Standard for the Format of ARPA Network Text Messages", David H.
        !           228:      Crocker (The Rand Corporation), John J. Vittal (Bolt Beranek and
        !           229:      Newman Inc.), Kenneth T. Pogran (Massachusetts Institute of
        !           230:      Technology), D. Austin Henderson, Jr.(Bolt Beranek and Newman Inc.) 21
        !           231:      November 1977.
        !           232: 
        !           233: RFC822 "Standard for the Format of ARPA Internet Text Messages", David H.
        !           234:      Crocker (University of Delaware), August 1982.
        !           235: 
        !           236: RFC882 "Domain Names - Concepts and Facilities", P. Mockapetris
        !           237:      (Information Sciences Institute, University of Southern California),
        !           238:      November 1983.
        !           239: 
        !           240: RFC883 "Domain Names - Implementation and Specification", P. Mockapetris
        !           241:      (Information Sciences Institute, University of Southern California),
        !           242:      November 1983.
        !           243: 
        !           244: RFC920 "Domain Requirements", J. Postel and J. Reynolds (Information
        !           245:      Sciences Institute, University of Southern California), October 1984.
        !           246: 
        !           247: RFC921 "Domain Names System Implementation Schedule - Revised", Jon Postel
        !           248:      (Information Sciences Institute, University of Southern California),
        !           249:      October 1984.
        !           250: 
        !           251: RFC973 "Domain System Changes and Observations", Paul Mockapetris
        !           252:      (Information Sciences Institute, University of Southern California),
        !           253:      January 1983. Supplements RFC 883.
        !           254: 
        !           255: RFC974 "Mail Routing and the Domain System", Craig Partridge (CSNET CIC,
        !           256:      BBN Laboratories, Inc.), January 1986.
        !           257: 
        !           258:                                -----------
        !           259: 
        !           260: This article appeared in CSNET-FORUM v2 #8 (8 Aug 86) with the title
        !           261: "Background on the Domain Naming System".
        !           262: 
unix.superglobalmegacorp.com

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.