Handbook of Infosec Terms 2.0/Handbook_of_Infosec_Terms_Version_2.0_ISSO.iso/text/rfcs/rfc0805.txt

Text File | 1996-05-07 | 12KB | 212 lines

Network Working Group                                          J. Postel Request for Comments:  805                                           ISI                                                          8 February 1982



                      Computer Mail Meeting Notes



 Introduction

   A meeting was held on the 11th of January 1982 at USC Information    Sciences Institute to discuss addressing issues in computer mail.    The attendees are listed at the end of this memo.  The major    conclusion reached at the meeting is to extend the    "username@hostname" mailbox format to "[e-mail]", where    the domain itself can be further structured.

Overview

   The meeting opened with a brief discussion of the objectives of the    meeting and a review of the agenda.

      The meeting was called to discuss a few specific issues in text       mail systems for the ARPA Internet.  In particular, issues of       addressing are of major concern as we develop an internet in which       mail relaying is a common occurance.  We need to discuss       alternatives in the design of the mail system to provide high       utility at reasonable cost.  One scheme suggested is to create       "mail domains" which are another level of addressing.  The ad hoc       scheme of source routing, while effective for some cases, is seen       to lead to some problems.  A key test of addressing schemes is the       procedure for sending copies of a reply to a message to the people       who received copies of the original message.  The key reference       documents for the meeting were RFCs 788, 799, and 801.

   Jon Postel gave a brief review of the NCP-to-TCP transition plan (RFC    801).  The emphasis was on mail, the internet host table, and the    role of a Host Name Server.

   The major part of the meeting was devoted to a wide ranging    discussion of the general mailbox identification problem.  In    particular, the notion of a hierarchial structure of name domains was    discussed, and the issues associated with name servers were discussed    including the types of information name servers should provide.

Name Domains

   One of the interesting ideas that emerged from this discussion was    that the "user@host" model of a mailbox identifier should, in

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    principle, be replaced by a "unique-id@location-id" model, where the    unique-id would be a globally unique id for this mailbox (independent    of location) and the location-id would be advice about where to find    the mailbox.  However, it was recognized that the "user@host" model    was well established and that so many different elaborations of the    "user" field were already in use that there was no point in persuing    this "unique-id" idea at this time.

   Several alternatives for the structuring and ordering of the    extensions to the "host" field to make it into a general    "location-id" were discussed.

      These basically involved adding more hierarchical name information       either to the right or the left of the @, with the "higher order"       portion rightmost or leftmost.  It was clear that the information       content of all these syntactic alternatives was the same, so that       the one causing least difficulty for existing systems should be       chosen.  Hence it was decided to add all new information on the       right of the @ sign, leaving the "user" field to the left       completely to each system to determine (in particular to avoid the       problem that some systems already use dot (.) internally as part       of user names).

   The conclusion in this area was that the current "user@host" mailbox    identifier should be extended to "[e-mail]" where "domain"    could be a hierarchy of domains.

      In particular, the "host" field would become a "location" field       and the structure would read (left to right) from the most       specific to the most general.

         For example: "[e-mail]" might be the mailbox of Jon          Postel on host F in the ISI complex of the Internet domain.

      Formally, in RFC733, the host-indicator definition rule would       become:

         host indicator = ( "at" / "@" ) domains

         domains = node / node "." domains

            Note only one "at" or "@" is allowed, and that the domains             form a hierarchy with the most general in scope last.

            And note that the choice of domain names must be             administratively controlled and the highest level domain             names must be globally unique.



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       The hierarchial domain type naming differs from source routing in       that the former gives absolute addressing while the latter gives       relative adressing.

Name Servers

   The discussion of name servers identified three separate name server    functions: "white pages", "unique-id to location-id", and    "location-id to address".

      The "white pages" service is a way of looking up a user by name       and other properties using pattern matching and may return several       data base "hits".  Each hit must have an associated unique-id.

      The "unique-id to location-id" service returns the character       string location-id where the unique-id is currently found.

      The "location-id to address" service returns a network address       (numeric) corresponding to the location-id.

         If the location-id is the name of a host in the current domain          it is clear that the address returned will be the address to          send the mail to, but if the location-id is that of some other          domain then the address returned may be either the address to          send the mail to, or the address of a name server for that          domain, and these two cases must be distinguished.

   The conclusion of this discussion was that a location-id to address    name service must be defined soon.  The other types of name servers    were not further discussed, and are not required in the    implemenation.

   Another aspect of the name server is returning additional information    besides the address.  In particular, for mail it is important to know    which mail procedures the destination implements (NCP/FTP, TCP/SMTP,    etc.).  Two approaches were discussed: one is coding the information    as service names (e.g., NCP/SMTP), and the other is by reference to    protocol and port numbers (e.g., PROTOCOL=6, PORT=25).  Another    suggestion was that the request ought to be "location-id,service"    (e.g., "ISIF.IN,MAIL") and the response ought to be the location-id,    address, protocol, and port.  A different way of getting this    information was suggested that instead of (or in addition to) having    this information in the name server, one should get this data from    the host itself via some sort of query or "who are you" protocol.

   Also discussed was the initial  provision for name service.  It seems    useful to start with a text file that can be accessed via FTP, and to    have both "Telnet-Like" (i.e., based on TCP) and "Datagram" (i.e.,



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    based on UDP) access to a query server.  This might be possible as an    extension of the IEN-116 name server.

   Another issue was the central vs. distributed implementation of the    name look up service.  It is recognized that separate servers for    each domain has administrative and maintenance advantages, but that a    central server may be a useful first step.  It is also recognized    that each distinct database should be replicated a few times and be    avialiable from distinct servers for robust and reliable service.

   An Example:

      Suppose that the new mailbox specification is of the form       [e-mail].

         e.g., [e-mail]

      A source host sending mail to this address first queries a name       server for the domain IN (giving the whole location "F.ISI.IN").

      The result of the query is either (1) the final address of the       destination host (F.ISI), or (2) the address of a name server for       ISI, or (3) the address of a forwarder for ISI.  In cases 1 and 3,       the source host sends the mail to the address returned.  In case       2,  the source host queries the ISI name server and ... (recursive       call to this paragraph).

Action Items:

   RFC 733 Revision

      To include the hierarchial host and domain naming procedure, and       to delete the features decommitted at the Computer Mail meeting on       10-JAN-79.

      By: Dave Crocker

      Due: 15-Feb-82

   Host Name Server Description

      To specify a way to get name to address conversions and to find       out about services offered.  Also how to get info on domain names.

      By: Jon Postel

      Due: 15-Feb-82



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    Transition Plan Revision

      To include new host and domain names.

      By: Jon Postel

      Due: 15-Feb-82

   SMTP Revision

      To include new host and domain names.

      By: Jon Postel

      Due: Unspecified

   Mail System Description Revision

      How to do mail systems, including use of SMTP and Host Name       Server.

      By: Jon Postel

      Due: Unspecified

   Conversion of User Programs and Mailer Programs.

      Programs have to handle dots in the "host" field.  Many programs       on many hosts will have to be modified to a greater or lesser       extent.  In many cases the modifications should be quite simple.

      By: A Cast of Thousands

      Due: Unspecified (See the Following Item)

   Set a date when it ok to send messages with dots in "host" field.

      The must be a date after which it is ok to send host fields with       dots  throughout the ARPANET and Internet world without the       recipients complaining.

      By: DARPA (Duane Adams)

      Due: 1-Mar-82







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 Attendees:

   Duane A. Adams    DARPA/IPTO    Adams@ISI           [phone]    Vint Cerf         DARPA/IPTO    Cerf@ISI            [phone]    Harry Forsdick    BBN           Forsdick@BBN        [phone]    Eric Schienbrood  BBN           shienbrood@bbn-unix [phone]    Bob Thomas        BBN           BThomas@BBND        [phone]    Bob Fabry         Berkeley      Fabry@Berkeley      [phone]    Bill Joy          Berkeley      unj@berkeley        [phone]    Gene Ball         CMU           Ball@CMUA           [phone]    Anil Agarwal      COMSAT        Agarwal@ISID        [phone]    David L. Mills    COMSAT        Mills@ISID          [phone]    Dave Crocker      Univ. Del     DCrocker@Udel       [phone]    Ray McFarland     DoD           McFarland@ISIA      [phone]    Dave Lebling      MIT           PDL@MIT-XX          [phone]    Paul Mockapetris  ISI           Mockapetris@ISIF    [phone]    Jon Postel        ISI           Postel@ISIF         [phone]    Carl Sunshine     ISI           Sunshine@ISIF       [phone]    Mark Crispin      Stanford U.   Admin.MRC@SCORE     [phone]    Bob Braden        UCL[A]        braden@ISIA      (uk) [phone]    Steve Kille       UCL           UCL-Netwiz@ISIE  (uk) [phone]    Bill Tuck         UCL           UKSAT@ISIE       (uk) [phone]    Marv Solomon      Univ. Wisc    Solomon@UWisc    Ed Taft           Xerox Parc    Taft@Parc-Maxc      [phone]



























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