rfc1123.txt

bind 9.3结合mysql数据库

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

   This RFC is an official specification for the Internet community.  It
   incorporates by reference, amends, corrects, and supplements the
   primary protocol standards documents relating to hosts.  Distribution
   of this document is unlimited.

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.



                           Table of Contents




   1.  INTRODUCTION ...............................................    5
      1.1  The Internet Architecture ..............................    6
      1.2  General Considerations .................................    6
         1.2.1  Continuing Internet Evolution .....................    6
         1.2.2  Robustness Principle ..............................    7
         1.2.3  Error Logging .....................................    8
         1.2.4  Configuration .....................................    8
      1.3  Reading this Document ..................................   10
         1.3.1  Organization ......................................   10
         1.3.2  Requirements ......................................   10
         1.3.3  Terminology .......................................   11
      1.4  Acknowledgments ........................................   12

   2.  GENERAL ISSUES .............................................   13
      2.1  Host Names and Numbers .................................   13
      2.2  Using Domain Name Service ..............................   13
      2.3  Applications on Multihomed hosts .......................   14
      2.4  Type-of-Service ........................................   14
      2.5  GENERAL APPLICATION REQUIREMENTS SUMMARY ...............   15




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RFC1123                       INTRODUCTION                  October 1989


   3.  REMOTE LOGIN -- TELNET PROTOCOL ............................   16
      3.1  INTRODUCTION ...........................................   16
      3.2  PROTOCOL WALK-THROUGH ..................................   16
         3.2.1  Option Negotiation ................................   16
         3.2.2  Telnet Go-Ahead Function ..........................   16
         3.2.3  Control Functions .................................   17
         3.2.4  Telnet "Synch" Signal .............................   18
         3.2.5  NVT Printer and Keyboard ..........................   19
         3.2.6  Telnet Command Structure ..........................   20
         3.2.7  Telnet Binary Option ..............................   20
         3.2.8  Telnet Terminal-Type Option .......................   20
      3.3  SPECIFIC ISSUES ........................................   21
         3.3.1  Telnet End-of-Line Convention .....................   21
         3.3.2  Data Entry Terminals ..............................   23
         3.3.3  Option Requirements ...............................   24
         3.3.4  Option Initiation .................................   24
         3.3.5  Telnet Linemode Option ............................   25
      3.4  TELNET/USER INTERFACE ..................................   25
         3.4.1  Character Set Transparency ........................   25
         3.4.2  Telnet Commands ...................................   26
         3.4.3  TCP Connection Errors .............................   26
         3.4.4  Non-Default Telnet Contact Port ...................   26
         3.4.5  Flushing Output ...................................   26
      3.5.  TELNET REQUIREMENTS SUMMARY ...........................   27

   4.  FILE TRANSFER ..............................................   29
      4.1  FILE TRANSFER PROTOCOL -- FTP ..........................   29
         4.1.1  INTRODUCTION ......................................   29
         4.1.2.  PROTOCOL WALK-THROUGH ............................   29
            4.1.2.1  LOCAL Type ...................................   29
            4.1.2.2  Telnet Format Control ........................   30
            4.1.2.3  Page Structure ...............................   30
            4.1.2.4  Data Structure Transformations ...............   30
            4.1.2.5  Data Connection Management ...................   31
            4.1.2.6  PASV Command .................................   31
            4.1.2.7  LIST and NLST Commands .......................   31
            4.1.2.8  SITE Command .................................   32
            4.1.2.9  STOU Command .................................   32
            4.1.2.10  Telnet End-of-line Code .....................   32
            4.1.2.11  FTP Replies .................................   33
            4.1.2.12  Connections .................................   34
            4.1.2.13  Minimum Implementation; RFC-959 Section .....   34
         4.1.3  SPECIFIC ISSUES ...................................   35
            4.1.3.1  Non-standard Command Verbs ...................   35
            4.1.3.2  Idle Timeout .................................   36
            4.1.3.3  Concurrency of Data and Control ..............   36
            4.1.3.4  FTP Restart Mechanism ........................   36
         4.1.4  FTP/USER INTERFACE ................................   39



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RFC1123                       INTRODUCTION                  October 1989


            4.1.4.1  Pathname Specification .......................   39
            4.1.4.2  "QUOTE" Command ..............................   40
            4.1.4.3  Displaying Replies to User ...................   40
            4.1.4.4  Maintaining Synchronization ..................   40
         4.1.5   FTP REQUIREMENTS SUMMARY .........................   41
      4.2  TRIVIAL FILE TRANSFER PROTOCOL -- TFTP .................   44
         4.2.1  INTRODUCTION ......................................   44
         4.2.2  PROTOCOL WALK-THROUGH .............................   44
            4.2.2.1  Transfer Modes ...............................   44
            4.2.2.2  UDP Header ...................................   44
         4.2.3  SPECIFIC ISSUES ...................................   44
            4.2.3.1  Sorcerer's Apprentice Syndrome ...............   44
            4.2.3.2  Timeout Algorithms ...........................   46
            4.2.3.3  Extensions ...................................   46
            4.2.3.4  Access Control ...............................   46
            4.2.3.5  Broadcast Request ............................   46
         4.2.4  TFTP REQUIREMENTS SUMMARY .........................   47

   5.  ELECTRONIC MAIL -- SMTP and RFC-822 ........................   48
      5.1  INTRODUCTION ...........................................   48
      5.2  PROTOCOL WALK-THROUGH ..................................   48
         5.2.1  The SMTP Model ....................................   48
         5.2.2  Canonicalization ..................................   49
         5.2.3  VRFY and EXPN Commands ............................   50
         5.2.4  SEND, SOML, and SAML Commands .....................   50
         5.2.5  HELO Command ......................................   50
         5.2.6  Mail Relay ........................................   51
         5.2.7  RCPT Command ......................................   52
         5.2.8  DATA Command ......................................   53
         5.2.9  Command Syntax ....................................   54
         5.2.10  SMTP Replies .....................................   54
         5.2.11  Transparency .....................................   55
         5.2.12  WKS Use in MX Processing .........................   55
         5.2.13  RFC-822 Message Specification ....................   55
         5.2.14  RFC-822 Date and Time Specification ..............   55
         5.2.15  RFC-822 Syntax Change ............................   56
         5.2.16  RFC-822  Local-part ..............................   56
         5.2.17  Domain Literals ..................................   57
         5.2.18  Common Address Formatting Errors .................   58
         5.2.19  Explicit Source Routes ...........................   58
      5.3  SPECIFIC ISSUES ........................................   59
         5.3.1  SMTP Queueing Strategies ..........................   59
            5.3.1.1 Sending Strategy ..............................   59
            5.3.1.2  Receiving strategy ...........................   61
         5.3.2  Timeouts in SMTP ..................................   61
         5.3.3  Reliable Mail Receipt .............................   63
         5.3.4  Reliable Mail Transmission ........................   63
         5.3.5  Domain Name Support ...............................   65



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RFC1123                       INTRODUCTION                  October 1989


         5.3.6  Mailing Lists and Aliases .........................   65
         5.3.7  Mail Gatewaying ...................................   66
         5.3.8  Maximum Message Size ..............................   68
      5.4  SMTP REQUIREMENTS SUMMARY ..............................   69

   6. SUPPORT SERVICES ............................................   72
      6.1 DOMAIN NAME TRANSLATION .................................   72
         6.1.1 INTRODUCTION .......................................   72
         6.1.2  PROTOCOL WALK-THROUGH .............................   72
            6.1.2.1  Resource Records with Zero TTL ...............   73
            6.1.2.2  QCLASS Values ................................   73
            6.1.2.3  Unused Fields ................................   73
            6.1.2.4  Compression ..................................   73
            6.1.2.5  Misusing Configuration Info ..................   73
         6.1.3  SPECIFIC ISSUES ...................................   74
            6.1.3.1  Resolver Implementation ......................   74
            6.1.3.2  Transport Protocols ..........................   75
            6.1.3.3  Efficient Resource Usage .....................   77
            6.1.3.4  Multihomed Hosts .............................   78
            6.1.3.5  Extensibility ................................   79
            6.1.3.6  Status of RR Types ...........................   79
            6.1.3.7  Robustness ...................................   80
            6.1.3.8  Local Host Table .............................   80
         6.1.4  DNS USER INTERFACE ................................   81
            6.1.4.1  DNS Administration ...........................   81
            6.1.4.2  DNS User Interface ...........................   81
            6.1.4.3 Interface Abbreviation Facilities .............   82
         6.1.5  DOMAIN NAME SYSTEM REQUIREMENTS SUMMARY ...........   84
      6.2  HOST INITIALIZATION ....................................   87
         6.2.1  INTRODUCTION ......................................   87
         6.2.2  REQUIREMENTS ......................................   87
            6.2.2.1  Dynamic Configuration ........................   87
            6.2.2.2  Loading Phase ................................   89
      6.3  REMOTE MANAGEMENT ......................................   90
         6.3.1  INTRODUCTION ......................................   90
         6.3.2  PROTOCOL WALK-THROUGH .............................   90
         6.3.3  MANAGEMENT REQUIREMENTS SUMMARY ...................   92

   7.  REFERENCES .................................................   93












Internet Engineering Task Force                                 [Page 4]




RFC1123                       INTRODUCTION                  October 1989


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.

   These documents are intended to provide guidance for vendors,
   implementors, and users of Internet communication software.  They
   represent the consensus of a large body of technical experience and
   wisdom, contributed by members of the Internet research and vendor
   communities.

   This RFC enumerates standard protocols that a host connected to the
   Internet must use, and it incorporates by reference the RFCs and
   other documents describing the current specifications for these
   protocols.  It corrects errors in the referenced documents and adds
   additional discussion and guidance for an implementor.

   For each protocol, this document also contains an explicit set of
   requirements, recommendations, and options.  The reader must
   understand that the list of requirements in this document is
   incomplete by itself; the complete set of requirements for an
   Internet host is primarily defined in the standard protocol
   specification documents, with the corrections, amendments, and
   supplements contained in this RFC.

   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



Internet Engineering Task Force                                 [Page 5]