Network Working Group                    Internet Engineering Task Force
Request for Comments: 1123                             R. Braden, Editor
                                                            October 1989


       Requirements for Internet Hosts -- Application and Support

Status of This Memo(RFC1122と同じ,略)

Summary

   This RFC is one of a pair that defines and discusses the requirements
   for Internet host software.  This RFC covers the application and
   support protocols; its companion RFC-1122 covers the communication
   protocol layers: link layer, IP layer, and transport layer.


1.  INTRODUCTION

   This document is one of a pair that defines and discusses the
   requirements for host system implementations of the Internet protocol
   suite.  This RFC covers the applications layer and support protocols.
   Its companion RFC, "Requirements for Internet Hosts -- Communications
   Layers" [INTRO:1] covers the lower layer protocols: transport layer,
   IP layer, and link layer.

  (中略)

   A good-faith implementation of the protocols that was produced after
   careful reading of the RFC's and with some interaction with the
   Internet technical community, and that followed good communications
   software engineering practices, should differ from the requirements
   of this document in only minor ways.  Thus, in many cases, the
   "requirements" in this RFC are already stated or implied in the
   standard protocol documents, so that their inclusion here is, in a
   sense, redundant.  However, they were included because some past
   implementation has made the wrong choice, causing problems of
   interoperability, performance, and/or robustness.

   This document includes discussion and explanation of many of the
   requirements and recommendations.  A simple list of requirements
   would be dangerous, because:

   o    Some required features are more important than others, and some
        features are optional.

   o    There may be valid reasons why particular vendor products that
        are designed for restricted contexts might choose to use
        different specifications.

   However, the specifications of this document must be followed to meet
   the general goal of arbitrary host interoperation across the
   diversity and complexity of the Internet system.  Although most
   current implementations fail to meet these requirements in various
   ways, some minor and some major, this specification is the ideal
   towards which we need to move.

(以下，略)

   INTRODUCTORY REFERENCES:

   [INTRO:1] "Requirements for Internet Hosts -- Communication Layers,"
        IETF Host Requirements Working Group, R. Braden, Ed., RFC-1122,
        October 1989.