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                               TOPS-20
                     ARPANET USER UTILITIES GUIDE






               This  manual   describes   the   TOPS-20
               utility  programs  available to users of
               the  Advanced  Research  Project  Agency
               Network    (ARPANET).    The   utilities
               reflect the TCP/IP protocols.



     OPERATING SYSTEM AND VERSION:      TOPS-20 (KL MODEL B), V6.0

     SOFTWARE AND VERSION:              TELNET Version 6
                                        FTP Version 6
                                        TSTATS Version 6
                                        IPHOST Version 6




        Digital Equipment Corporation, Maynard, Massachusetts
                                                                Page 2


                                             First Printing, June 1978
                                                Updated, November 1979
                                                 Updated, January 1980
                                                 Revised, October 1983



The information in this document is subject to change  without  notice
and  should  not  be  construed  as  a commitment by Digital Equipment
Corporation.  Digital Equipment Corporation assumes no  responsibility
for any errors that may appear in this document.

The software described in this document is furnished under  a  license
and  may  only  be used or copied in accordance with the terms of such
license.

Digital Equipment Corporation assumes no responsibility for the use or
reliability  of  its  software  on  equipment  that is not supplied by
DIGITAL or its affiliated companies.





  Copyright  C , 1978, 1980, 1983 by Digital Equipment Corporation.
                         All Rights Reserved.






The following are trademarks of Digital Equipment Corporation:

     DIGITAL             DECsystem-10        MASSBUS
     DEC                 DECtape             OMNIBUS
     PDP                 DIBOL               OS/8
     DECUS               EDUSYSTEM           PHA
     UNIBUS              FLIP CHIP           RSTS
     COMPUTER LABS       FOCAL               RSX
     COMTEX              INDAC               TYPESET-8
     DDT                 LAB-8               TMS-11
     DECCOMM             DECSYSTEM-20        TYPESET-11
                         DECSYSTEM-2020      TYPESET-20
                                                                Page 3


CHAPTER 1       INTRODUCTION TO THE TOPS-20 ARPANET USER UTILITIES

        1.1     USING ARPANET UTILITIES  . . . . . . . . . . . . . 1-1
        1.2     INVOKING THE UTILITIES . . . . . . . . . . . . . . 1-2
        1.3     TYPING FILE SPECIFICATIONS . . . . . . . . . . . . 1-2


CHAPTER 2       THE TELNET PROGRAM

        2.1     INTRODUCTION . . . . . . . . . . . . . . . . . . . 2-1
        2.2     USERS AND SERVERS  . . . . . . . . . . . . . . . . 2-1
        2.3     CREATING A TELNET CONNECTION . . . . . . . . . . . 2-2
        2.4     TERMINAL INPUT MODES . . . . . . . . . . . . . . . 2-4
        2.5     RUNNING TELNET . . . . . . . . . . . . . . . . . . 2-4
        2.5.1     CONNECT Command  . . . . . . . . . . . . . . . . 2-6
        2.5.2     TELNET Ports . . . . . . . . . . . . . . . . . . 2-7
        2.6     EXITING TELNET . . . . . . . . . . . . . . . . . . 2-7
        2.7     GETTING HELP WITH TELNET . . . . . . . . . . . . . 2-8
        2.8     TELNET COMMAND CHARACTER . . . . . . . . . . . . . 2-8
        2.9     TELNET COMMANDS  . . . . . . . . . . . . . . . . . 2-9
        2.10    CHANGING TELNET PARAMETERS . . . . . . . . . . .  2-12
        2.11    CREATING A TELNET.CMD FILE . . . . . . . . . . .  2-14
        2.12    CREATING A TELNET LOG FILE . . . . . . . . . . .  2-14
        2.13    TAKING COMMANDS FROM FILES . . . . . . . . . . .  2-15
        2.14    TELNET MESSAGES  . . . . . . . . . . . . . . . .  2-15


CHAPTER 3       THE FILE TRANSFER PROGRAM

        3.1     INTRODUCTION . . . . . . . . . . . . . . . . . . . 3-1
        3.2     USING FTP  . . . . . . . . . . . . . . . . . . . . 3-1
        3.3     RUNNING FTP  . . . . . . . . . . . . . . . . . . . 3-2
        3.4     EXITING FTP  . . . . . . . . . . . . . . . . . . . 3-4
        3.5     GETTING HELP WITH FTP  . . . . . . . . . . . . . . 3-5
        3.6     FTP COMMANDS . . . . . . . . . . . . . . . . . . . 3-9
        3.6.1     Requesting Data Transfers Or Remote File System 
                  Service  . . . . . . . . . . . . . . . . . . . . 3-9
        3.6.2     FTP Information Commands . . . . . . . . . . .  3-15
        3.6.3     Controlling FTP Transfer Parameters  . . . . .  3-16
        3.7     RESPONSE CODES AND MESSAGES  . . . . . . . . . .  3-18
        3.7.1     Response-Coding System . . . . . . . . . . . .  3-19


CHAPTER 4       TSTATS

        4.1     INTRODUCTION . . . . . . . . . . . . . . . . . . . 4-1
        4.2     RUNNING TSTATS . . . . . . . . . . . . . . . . . . 4-1
        4.3     INTERPRETING TSTATS  . . . . . . . . . . . . . . . 4-2


CHAPTER 5       IPHOST

        5.1     INTRODUCTION . . . . . . . . . . . . . . . . . . . 5-1
        5.2     RUNNING IPHOST . . . . . . . . . . . . . . . . . . 5-1
        5.3     EXITING IPHOST . . . . . . . . . . . . . . . . . . 5-1
                                                                Page 4


        5.4     GETTING HELP WITH IPHOST . . . . . . . . . . . . . 5-2
        5.5     IPHOST COMMANDS  . . . . . . . . . . . . . . . . . 5-2
        5.6     IPHOST MESSAGES  . . . . . . . . . . . . . . . . . 5-5
                                                                Page 5














                               PREFACE



The TOPS-20 ARPANET User Utilties  Guide  is  written  for  users  who
communicate  with remote sites on the Advanced Research Project Agency
NETwork (ARPANET).  Before using this manual, you should  be  familiar
with  the  information  contained  in  the  latest  version of Getting
Started with TOPS-20,  the  TOPS-20  User's  Guide,  and  the  TOPS-20
Commands Reference Manual.

This manual contains detailed information  on  the  following  TOPS-20
ARPANET   utility   programs:    TELNET,   FTP,  TSTATS,  and  IPHOST.
Information in the manual is current as of the version of the  utility
stated  on  the  title  page  of  this manual.  Tutorial and reference
material is available in each chapter to accommodate inexperienced and
experienced ARPANET users.

The following  conventions  are  used  in  the  TOPS-20  ARPANET  User
Utilties Guide:

<RET>                    Indicates that you press the RETURN key.   On
                         some terminals, this key is labeled CR.

<ESC>                    Indicates that you  press  the  ESCAPE  (ESC)
                         key.    This  key  is  labeled  ALT  on  some
                         terminals.

<CTRL/X>                 Indicates that you press the  CONTROL  (CTRL)
                         key  and at the same time press the letter or
                         symbol indicated after the slash (/).

file spec                Indicates a file specification.

The current version of the following TOPS-20 documents are  referenced
in this manual:

     TOPS-20 User's Guide

     TOPS-20 Monitor Calls User's Guide











                              CHAPTER 1

          INTRODUCTION TO THE TOPS-20 ARPANET USER UTILITIES



The TOPS-20 ARPANET user utility programs allow users  to  connect  to
remote sites on the Advanced Research Project Agency NETwork (ARPANET)
and to function as local users at the remote site.  Once connected  to
a  remote  site,  you have access to the resources of the remote site.
You will be  able  to  create  directories;   create,  edit,  and  run
programs;  create and edit files;  transfer files and data between the
local and the remote site;  communicate with users at both  the  local
and remote site;  and obtain information about sites and the status of
connections between sites.

The following utility programs are described in this manual:

      o  The TELNET program, which  allows  you  to  communicate  with
         remote sites (Chapter 2)

      o  The FTP program, which allows you to transfer files and  data
         between local and remote sites (Chapter 3)

      o  The TSTATS program, which allows you to check the  status  of
         host connections (Chapter 4)

      o  The IPHOST program, which allows you to get information about
         hosts.   IPHOST also allows an operator to cycle the ARPANET.
         (Chapter 5)



1.1  USING ARPANET UTILITIES

Three manuals, Getting Started with TOPS-20, the TOPS-20 User's Guide,
and  the TOPS-20 Commands Reference Manual, describe the commands that
are needed to use the TOPS-20 operating system.  There  are  commands,
however,  that  are specific to ARPANET users.  The commands needed to
use the TOPS-20 ARPANET utilities are described in this manual.
INTRODUCTION TO THE TOPS-20 ARPANET USER UTILITIES            Page 1-2


1.2  INVOKING THE UTILITIES

To invoke the ARPANET utilities, you need to  be  logged  in  to  your
system.  Type the name of the program after the TOPS-20 prompt (@) and
press the RETURN key.  This invokes the utility program.  The  utility
then prompts you for input.  The general format for invoking utilities
is:

     @ Utility name <RET>

     Utility prompt



1.3  TYPING FILE SPECIFICATIONS

The ARPANET utilities allow you to communicate with  hosts  that  have
operating  systems that are different from the one you are working on.
For this reason, each utility described in this manual  documents  the
format  for  typing  file  specifications.  The use of recognition and
wildcards is also documented on a chapter by chapter basis.











                              CHAPTER 2

                          THE TELNET PROGRAM



2.1  INTRODUCTION

TELNET is  a  TOPS-20  utility  that  provides  communication  between
ARPANET  hosts  by  establishing  a  connection  between a local and a
remote host.  This connection makes it appear as if you  are  a  local
user  at  the  remote  site.   TELNET  accomplishes this by converting
terminals attached to a host running TOPS-20 software  into  a  TELNET
connection.



2.2  USERS AND SERVERS

ARPANET installations, including Terminal Access  Controllers  (TACs),
are  classified  as  users  or  servers.   These  terms  are  used  to
distinguish the manner in which resources are shared.  The  terms  are
also  used  to  determine  the  roles  of  each  host  during a TELNET
connection.

The  way  resources  are  shared  is  established  by   each   ARPANET
installation.   A  server  installation shares its resources among all
ARPANET sites.  A user uses the resources of other sites, but does not
share  its  resources.  The classification of a resource as a user may
be determined by security requirements or by lack of resources at  the
site.   TACs, for example, have no resources to share.  Do not attempt
a TELNET connection to a host classified as a user.

The terms user and server also define the function of  the  two  hosts
during  a  TELNET  connection.   Used  in  this  manner, the term user
designates the host that is using the resources of another site.   The
server  is  providing the service.  For example, two sites, Host A and
Host B, are classified as servers.  Host A establishes a connection to
Host  B.   For  the  duration  of  the  TELNET  connection,  Host A is
classified as a user, and Host B acts as a server.

In addition to an understanding of the terms user and server, you must
also  be  aware of the rules governing TELNET connections at your site
and at the remote site.  Check with your System Manager regarding  the
rules  and  times  for TELNET connections.  Also, become familiar with
the requirements of the remote sites to which  you  make  connections.
THE TELNET PROGRAM                                            Page 2-2


This  is  necessary  because  some  sites  require  that you set up an
account with a specific individual at their site.  Some sites  require
a  password  unique to the individual user, while others allow a group
password such as "guest".  Some sites restrict TELNET connections to a
designated  time  interval.   Reading the ARPANET RESOURCE HANDBOOK, a
publication of the Network Information Center (NIC), is  helpful.   At
least  one  copy  is  available at each ARPANET site.  The handbook is
organized by sites and contains such information as:

      o  Address and personnel contacts

      o  Main function and interest

      o  Tables containing  host  names  and  addresses,  IMP  number,
         status (Server, User, TAC)

      o  Service schedules

      o  Typical load and peak load time

      o  Hardware and operating system



2.3  CREATING A TELNET CONNECTION

Creating  a  satisfactory  TELNET  connection  is  basic  to   TELNET.
Therefore,   understanding   the   principles   of   TELNET   protocol
negotiations helps you:

      o  Request added (more sophisticated) capabilities

      o  Request different capabilities

      o  Avoid option commands that will not be honored

      o  Avoid unnecessary option commands

      o  Make efficient use of available commands

TELNET  negotiations  for  assigning  capabilities   to   the   TELNET
connection  and  the TELNET connection itself are invisible to you.  A
completed connection appears to be direct.

Once you type the TELNET command, a set of  "current  modes"  for  the
TELNET  connection is available to you and TELNET.  These values, such
as local echo, are a set of minimal capabilities that  most  hosts  on
the   ARPANET   possess.    The  current  modes  form  the  basis  for
negotiations;  they are the default modes and  exist  for  the  TELNET
connection except as specifically changed by TELNET negotiations.

Following the establishment of the connection, TELNET has access to:
THE TELNET PROGRAM                                            Page 2-3


      o  The default values

      o  The actual capabilities of the user terminal

      o  The actual capabilities of the server terminal

      o  The preferences of user and server

         --  As they exist in files (such files are  helpful  but  are
             optional)

         --  As given in TELNET commands by user or server

TELNET considers all the above factors and selects  a  set  of  values
representing  a "best fit" for the TELNET connection.  TELNET resolves
differences in capabilities  and  option  requests  according  to  the
following practices:

      o  A server is expected to allow a  user  all  terminal  options
         that the server supplies to local users.

      o  Either party to a proposed connection may refuse to change  a
         default mode.  Each party must accept the other's refusal.

      o  All hosts are expected to use their local terminal in such  a
         way  as  to  appear to be dealing with the TELNET connection.
         For example, if the TELNET connection has been negotiated  as
         having  local  echo,  both  hosts for this connection must be
         prepared to interpret local echo.

      o  Option requests may be made  during  the  TELNET  session  to
         change  the  TELNET  connection  to suit a changed condition.
         Option requests may then be negotiated  back  to  the  TELNET
         connection.

      o  A rejected option request  should  never  be  repeated  until
         something  changes.  For example, wait until a different task
         or information is received from the other end.

      o  A bidirectional 7- or 8-bit byte is the facility supported by
         the TOPS-20 user TELNET program.  The most significant bit is
         controlled by the TRANSPARENT command.  See Section 2.9 for a
         discussion of the TRANSPARENT command.

Most TELNET connections are negotiated by the program.  Connections to
hosts  with  very different hardware/software facilities, however, may
require several option requests.
THE TELNET PROGRAM                                            Page 2-4


2.4  TERMINAL INPUT MODES

Because TELNET communicates with foreign hosts,  TELNET  distinguishes
between  terminal input that is a command to the program, and terminal
input  that  is  part  of   the   user-to-server   or   server-to-user
communication.  TALK mode and EXTENDED TALK mode serve these functions
in TELNET.

When a connection to a TELNET remote host is  established,  you  enter
TALK mode.  In this mode, you are talking directly to the remote host.
You are no longer dealing with the TELNET command protocol.  The  only
exceptions to this rule are:

      o  If you are  not  in  TRANSPARENT  mode,  TALK  mode  will  be
         affected.  TRANSPARENT mode is discussed in Section 2.9.

      o  OPAQUE and PAGE mode also affect TALK mode.  These modes  are
         discussed in Section 2.10.

      o  If you  hit  the  escape  character,  you  are  automatically
         returned to Command level.

TALK mode is the only mode in which many of the  TELNET  commands  and
arguments  are  valid.   Command  descriptions  note  whether  or  not
commands are valid in TALK mode.

EXTENDED TALK mode allows you to return to the local host  to  perform
certain  tasks,  such  as  logging  file usage or renegotiating TELNET
parameters, without interfering with the  terminal  function  you  are
performing  at  the remote host.  Once a command has been completed in
EXTENDED TALK mode, you are  returned  to  TALK  mode.   Enabling  the
EXTENDED TALK function of TELNET is discussed in Section 2.9.

Generally, EXTENDED TALK mode is entered from TALK mode.  If, however,
you  create  a  TELNET.CMD  file (see Section 2.11 for a discussion of
TELNET.CMD files), you can enter EXTENDED TALK mode  as  soon  as  you
establish  a  TELNET connection.  Command descriptions note whether or
not the command is valid in EXTENDED TALK mode.



2.5  RUNNING TELNET

To run the TELNET program, you must  already  be  logged  in  to  your
system.   You  can  determine if the ARPANET is available by using the
INFORMATION (ABOUT) ARPANET-STATUS command.  This  command  gives  you
information about the ARPANET status:

     @INFORMATION (ABOUT) ARPANET <RET>
     Local ARPANET host name is DEC-TOPS20, Internet address is
     10.0.0.79
     Network interface is down
     Network interface output is disabled
     Network service is enabled
     Last network interface off transition: 18-Nov-83 14:16:17
THE TELNET PROGRAM                                            Page 2-5


     @

To run TELNET, type TELNET in response to the TOPS-20 prompt.  You are
then  prompted  with  the  TELNET  prompt  followed  by  a right angle
bracket(>), as in:

     @TELNET <RET>
      TELNET>

Following this prompt, type the name, nickname, or host id of the host
you  are  attempting  to  connect  to.   You  then  receive  a message
indicating the status of the connection that is being  attempted.   In
the following example, there is a successful connection to the foreign
host.

EXAMPLE:

     Market - LCG's Timesharing System, TOPS-20 Monitor 6(5646)
     @LOGIN PAETZOLD (PASSWORD)    <RET>
      Job 29 on TTY233 15-Nov-83 14:02:82
     @TELNET <RET>
      TELNET>RADC-TOPS20 <RET>
     Trying...Open

In the next  example,  however,  TELNET  can  not  make  a  successful
connection.   This  example  assumes that you are already logged in to
your system.

EXAMPLE:  @TELNET<RET>
           TELNET>SU-SCORE<RET>
            Trying...Host dead, not scheduled up, up on Wednesday at 3:00 P.M. EST
          @

If you are not able to make a successful connection, either  choose  a
different  host  or  attempt a connection at the time indicated by the
TELNET message.  For a list  of  available  TELNET  hosts,  check  the
ARPANET RESOURCE HANDBOOK.

Once you are  connected  to  an  ARPANET  site  by  means  of  TELNET,
typically  the  herald  for  that system appears.  (Some ARPANET sites
have no herald.  At this point, it is necessary for you to log  in  to
the  remote system.  Most ARPANET sites provide any unique information
needed to log in to that site.  Therefore, be sure to read the  herald
before you attempt to log in to the foreign host.

The example below shows the procedure  for  logging  in  to  your  own
system and then establishing a TELNET connection and logging in to the
foreign host.

     Market - LCG's Timesharing System , TOPS-20 Monitor 6(5646)
     @LOGIN PAETZOLD (PASSWORD)        <RET>
      Job 29 on TTY233 15-Nov-83 14:02:38 <RET>
     @TELNET <RET>
      TELNET>RADC-TOPS20 <RET>
       Trying...Open
THE TELNET PROGRAM                                            Page 2-6


      Rome Air Development Center, TOPS-20 Monitor 6(5646)
     @LOGIN PAETZOLD (PASSWORD)  <RET>
      Job 11 on TTY64, last login 15-Nov-83 13:58:58
      15-Nov-83 14:02:50, Up 7:53:27, 9+2 jobs
     @



2.5.1  CONNECT Command

The CONNECT command can be used to establish a TELNET connection to  a
remote site.  The CONNECT command takes the form:

     @TELNET CONNECT HOST-ID <RET>

where HOST-ID is the name of the remote site you want to  connect  to.
Using the CONNECT command eliminates the TELNET> prompt.

The following is an example of the CONNECT command:

     @TELNET CONNECT DEC-MARLBORO
      Trying...Open
     Market - LCG'S Timesharing System, TOPS-20 Monitor 6(5646)
     @

The CONNECT command is also  used  to  establish  a  connection  to  a
specified   host  on  a  designated  contact  port.   For  a  detailed
explanation of ports, see the following section.  To use  the  CONNECT
command  to establish a connection on a specified port, you must be in
EXTENDED TALK mode.  The CONNECT command takes the form:

     CONNECT (TO) INTERNET (HOST) host (ON PORT) port

where host is either a recognized host name or a network name followed
by  four  8-bit  decimal numbers specifying the fields of the INTERNET
address.  The numbers are separated from each other by periods.

The port specification for an  INTERNET  connection  consists  of  two
8-bit decimal numbers from 1 to 255, separated by a period or a space.
The port default is 0,23.

An example of the use of the INTERNET CONNECT command is given below:

     TELNET>CONNECT (TO) INTERNET (HOST)DEC-MARLBORO (ON PORT)SYSTAT <RET>
     Trying...Open
     Wed 15-Nov-83 14:11:05  Up 19:58:14
     21+12 Jobs  Load av   3.04  2.05  1.87
     Job     Line    Program   User         Foreign Host
      8      227     OPHIST    REHILL.OPHIST
     11       33     EXEC      EIBEN
     13        7     HELP      SHERWIN
     15       36     MM        TITCOMB
     .
     .
     .
THE TELNET PROGRAM                                                      Page 2-7


     Connection closed by foreign host



2.5.2  TELNET Ports

TELNET utilizes ports with the CONNECT  command  when  establishing  a
connection  to  a  particular  TELNET  task.   Once  the task has been
executed by TELNET, the connection is closed by the remote host.

The argument line for the use of ports takes the form:

     TELNET>CONNECT (TO) INTERNET (HOST) host name (ON PORT) port

where host name is the name of a recognized host name or host id  (see
the ARPANET Handbook) and port is one of the following:

     DAYTIME         DISCARD    ECHO       FINGER   FTP
     OLD-TELNET      SYSTAT     TELNET     TEXT     TTYTST

You can use recognition and a question mark for  help  in  typing  the
correct argument line.

TELNET then establishes a connection to the remote host, performs  the
task,  and closes the connection.  The following example shows the use
of ports in a TELNET session.

     TELNET>INTERNET (HOST) DEC-MARLBORO (ON PORT) SYSTAT <RET>
      Trying...Open
      Wed 15-Nov-83 14:11:05  Up 19:58:14
      21+12 Jobs  Load av  3.04  2.05  1.87
     Job   Line   Program   User       Foreign host
      8    227    OPHIST    REHILL.OPHIST
     11     33    EXEC      EIBEN
     13      7    HELP      SHERWIN
     15     36    MM        TITCOMB
     .
     .
     .
     Connection closed by foreign host



2.6  EXITING TELNET

Two commands are used to exit from TELNET:  CLOSE and EXIT.

To exit from TELNET TALK mode using the CLOSE command, type  <CTRL/~>C
in response to the TELNET command prompt.  The <CTRL/~>C is not echoed
on your terminal.  You are then informed that the connection has  been
closed:

     Command: <CTRL/~>C
     Connection closed
     @
THE TELNET PROGRAM                                            Page 2-8


The CLOSE (Connection) command closes the network  connection  to  the
remote  host  from EXTENDED TALK mode.  Using this command returns you
to the TOPS-20 command level.  To use this command, type:

     TELNET>CLOSE <RET>
     @

The EXIT or Quit (from TELNET) command returns you  to  command  level
without closing the network connection.  To use this command, type:

     TELNET>EXIT <RET>
     TELNET>



2.7  GETTING HELP WITH TELNET

There are two ways of getting  help  in  using  TELNET.   Typing  a  ?
provides  information  on  the  single  command  or  message  that  is
currently being displayed on the terminal.  After typing  the  ?   and
getting  help,  you  are  prompted  for  the  next  argument needed to
complete your command:

     TELNET>ESCAPE (CHARACTER IS)? escape character in quotes
       or ASCII code for character in octal

To get information  on  running  the  TELNET  program,  use  the  HELP
command.   Typing  either  HELP  or  TELNET  HELP in response to the @
prompt prints a brief help text on how to use TELNET.



2.8  TELNET COMMAND CHARACTER

The TELNET protocol sends data to the foreign host.  This data is  not
interpreted by TELNET.  It is only transmitted across the network.

The ^^character, which is the ASCII character 36, is the basic command
character TELNET uses to control the transmission of data.  On a VT100
series terminal, this character is entered as <CTRL/~>.

The  <CTRL/~>  is  the  TELNET  command  character.   This   character
interacts  with the TELNET program.  The command character is followed
by an additional character to specify the action to be taken.  If  the
command  character  is followed by itself, as in <CTRL/~><CTRL/~>, the
command character is transmitted to the remote host.

The command character is not echoed on  your  terminal.   However,  in
this manual, command characters are shown in the examples.
THE TELNET PROGRAM                                            Page 2-9


2.9  TELNET COMMANDS

TELNET commands are specified by typing the TELNET  command  character
<CTRL/~> followed by another character that specifies the action to be
taken, as in <CTRL/~>P.  The command sequence that  you  type  is  not
echoed on your terminal.

Some of the TELNET commands are only legal in TALK mode, while  others
can  only be used in EXTENDED TALK mode.  These commands are explained
in detail below.


QUESTION MARK (?) COMMAND:

The Question Mark command, which is input by typing a <CTRL/~>?, gives
information  about  what is needed to complete your current task.  The
following example shows the use of the ?  command:

     <CTRL/~>?
     Type a single character command:
     ?   This message
     A   Send ATTN
     B   Send BREAK
     C   Close connection
     O   Abort output
     P   Push to inferior EXEC
     S   Status of TELNET connection
     Q   Quit
     T   Transparent Mode toggle
     X   Enter extended command mode
     Typing the escape character twice sends it to the host.
     Command:


ATTN (KEY) COMMAND:

The ATTN command can only be used in TALK mode.  Its  function  is  to
send   the  TELNET  "interrupt  process"  protocol  sequence  for  the
"Attention" signal.  This command is used primarily for MULTICS or IBM
systems.  To use this command, type <CTRL/~>A in TALK mode,as shown in
the following example:

     <CTRL/~>A


BREAK COMMAND:

The BREAK command can only be  used  in  TALK  mode.   Use  the  Break
command  to send the TELNET "break" sequence and to terminate whatever
task is being performed at the remote host.  To use this command, type
CTRL/~B in TALK mode, as in the following example:

     <CTRL/~>B
THE TELNET PROGRAM                                           Page 2-10


CLOSE (CONNECTION) COMMAND:

As discussed previously, the CLOSE command is one  method  of  exiting
from  TELNET and closing the ARPANET connection.  When you are in TALK
mode, typing the <CTRL/~>C returns you to the  TELNET  command  level.
When  in  EXTENDED  TALK  mode, typing CLOSE in response to the TELNET
prompt closes the connection and returns you to TELNET command  level.
An example of the use of the CLOSE command is given below.

Using the CLOSE command from TALK mode:

     <CTRL/~>C
     Connection closed by foreign host

Using the CLOSE Command from EXTENDED TALK mode:

     TELNET>Close <RET>
     Connection closed by foreign host


ABORT (OUTPUT) COMMAND:

The ABORT command is legal  only  in  TALK  mode.   When  you  type  a
<CTRL/~>O, the TELNET "abort output" signal is sent to the remote host
and any output from the remote host is halted.  To use  this  command,
type:

     <CTRL/~>O


PUSH (COMMAND LEVEL) COMMAND:

You can use the PUSH command in either TALK  or  EXTENDED  TALK  mode.
The  PUSH  command  functions in the same manner as it does at TOPS-20
command level.  Use this command when you wish to perform  a  task  at
your local host.  When you have completed the task, typing POP returns
you to TELNET TALK mode.

Not only is the PUSH command useful for doing a temporary task at  the
local host and then returning to TELNET, the command also protects you
against accidentally logging  out  while  you  still  have  an  active
connection.   You  cannot  log  out  once  you  have executed the PUSH
command.

To use this command in TALK mode, type <CTRL/~>P as in:

     <CTRL/~>P

To use this command in EXTENDED TALK mode, type PUSH  in  response  to
the TELNET command prompt, as in:

     TELNET>PUSH <RET>


STATUS (OF TELNET CONNECTION) COMMAND:
THE TELNET PROGRAM                                           Page 2-11


The STATUS command allows you to ask the remote host to send a message
indicating  that it is still available.  This command is only legal in
TALK  mode.   Most  often  you  receive  a  job/system  message   that
identifies  the  remote  host.   The minimum response you receive is a
yes.

To use the STATUS command, type <CTRL/~>S in response  to  the  TELNET
prompt.   Neither  the  control nor the command character is echoed on
your terminal.  The most frequent response to this command  is  listed
in the example given below:

     @<CTRL/~>S <RET>
     This is DEC-TOPS20, ARPANET TCP/IP Development System, TOPS-20 Monitor 6(5646)
     Connected to host DEC-TOPS20 via Internet
     New TELNET protocol
     Remote host is echoing
     Line editor disabled
     GA's are suppressed
     Host is not sending binary
     Transparent mode disabled
     Opaque mode disabled
     Page mode disabled
     No log file
     No TAKE file
     Simple talk command mode
     Remote host status reply:
      09:38:55 Used 0:00:00.2 in 0:00:12, Load   0.31


[NO] TRANSPARENT (MODE) COMMAND:

The TRANSPARENT command controls whether or not the  most  significant
bit  of  the 8-bit character (also called the edit key) is transmitted
to the remote host as an editing character.   This  command  is  legal
only  in  TALK mode.  In TRANSPARENT mode, the edit key functions as a
character modifier at the remote  host.   When  the  [NO]  TRANSPARENT
command  is chosen, the edit key is suppressed and cannot be used as a
character modifier.

To enable TRANSPARENT mode, type either <CTRL/~>T or TRANSPARENT.   To
suppress  the  edit  key,  use  the  NO TRANSPARENT command, which you
enable by typing a double <CTRL/~>T.

The following example  shows  the  use  of  the  TRANSPARENT  command.
Remember  neither  the  control  character nor the single character is
echoed on your terminal.

     <CTRL/~>T


[NO] EXTENDED (COMMAND MODE AUTOMATICALLY WHEN ESCAPE CHARACTER TYPED)
COMMAND:

The EXTENDED command controls entry into the  EXTENDED  TALK  mode  of
TELNET.   You  can  use  the  EXTENDED  command in two ways:  to enter
THE TELNET PROGRAM                                           Page 2-12


EXTENDED TALK mode immediately  upon  entering  TELNET,  or  to  enter
EXTENDED TALK mode from TALK mode.

If you have created a TELNET.CMD file,  you  can  place  the  EXTENDED
command  in  this  file.   If you use the EXTENDED command, you bypass
TALK mode and automatically enter EXTENDED TALK mode when you  make  a
TELNET  connection.   The  default  for the EXTENDED command is the NO
EXTENDED command.  If the default is used, you enter  TALK  mode  when
you enter TELNET.


                                 NOTE

               If you set EXTENDED in  your  TELNET.CMD
               file,   you   cannot   send  the  escape
               character <CTRL/~> to the remote host.


The EXTENDED command can also be used from TALK mode.  When you are in
TALK  mode,  typing  <CTRL/~>X places you in EXTENDED TALK mode.  This
allows you to perform certain TELNET tasks at your local site  without
interfering with the task being performed at the remote site.



2.10  CHANGING TELNET PARAMETERS

Four  commands  are  available  for   changing   TELNET   transmission
parameters:   ECHO,  LINE,  OPAQUE, and PAGE.  Descriptions of each of
these commands are given below.


[NO] ECHO (BY REMOTE HOST) COMMAND:

The ECHO command controls which host performs echoing of  user  input.
When  the NO ECHO command is enabled, echoing occurs at the local host
and is  under  TELNET  protocol  control.   If  the  ECHO  command  is
specified,  the  remote  host  handles echoing.  The ECHO parameter is
part of TELNET negotiations and must be agreed to by the remote  host.
If  the  remote  host does not agree to handle echoing, TELNET reverts
back to local echo.   On  most  occasions,  TELNET  negotiates  remote
echoing when establishing the TELNET connection.

Once a connection is in effect, ECHO or NO ECHO can be  used  only  in
TALK mode.  To use the ECHO command, type:

     @TELNET>ECHO<RET>


[NO] LINE (EDITOR FOR LOCAL ECHO CONNECTIONS) COMMAND:

The LINE command controls the use of the  TOPS-20  editing  characters
rubout,  CTRL/R,  CTRL/W,  and  CTRL/U, as well as the manner in which
text is sent to the remote host.  The LINE command can  be  used  only
when local echoing is in effect.
THE TELNET PROGRAM                                           Page 2-13


When the LINE command is enabled,  the  rubout,  CTRL/R,  CTRL/W,  and
CTRL/U  characters  can  be used.  Also, no text is sent to the remote
host until a carriage return or  a  line  feed  is  typed.   The  LINE
command is useful for connections to a line-oriented system.

To use the LINE command, type LINE in response to the TELNET prompt:

     @TELNET>LINE <RET>


[NO] OPAQUE (MODE) COMMAND:

The OPAQUE command controls the degree of local terminal handling that
is  done during a TELNET session.  When the OPAQUE command is enabled,
the local host continues to  handle  such  functions  as  padding  and
keeping  track  of  the  cursor's  position.   The  OPAQUE  command is
generally used with terminals whose capabilities  are  different  than
the terminal you are working on.

In addition, when the OPAQUE command is enabled,  nulls  are  ignored;
and character conversion may take place.  You will, in most instances,
not be able to use a display editor at the remote  host.   The  OPAQUE
and  PAGE  commands  must  both  be enabled in order to have automatic
holding at the end of the terminal screen.

The NO OPAQUE command is the TELNET default.  The  NO  OPAQUE  command
specifies that the remote host will handle all terminal functions.  No
local terminal handling is done.

To use the OPAQUE command, type  OPAQUE  in  response  to  the  TELNET
prompt, as in the following example:

     TELNET>OPAQUE<RET>


[NO] PAGE (MODE) COMMAND:

The PAGE command controls  whether  or  not  the  local  host  handles
terminal  paging.   When  the  PAGE command is enabled, the local host
handles paging using the CTRL/Q and CTRL/S characters.   There  is  no
way  to  send  these characters to the remote host.  If you enable the
PAGE command, you should also enable the OPAQUE command,  since  these
commands,  used  jointly,  tell  the local host how many lines of text
have been input.

Use the PAGE command when you need to have paging in  effect  and  the
remote  host will not or can not handle this task.  For example, VT100
terminals in smooth scroll  mode  require  faster  handling  than  the
networks allow.

NO PAGE is the TELNET default command.  When the NO PAGE command is in
effect,  the  CTRL/Q  and  CTRL/S  characters are passed to the remote
host.

To use the PAGE command, type PAGE in response to the  TELNET  prompt,
THE TELNET PROGRAM                                           Page 2-14


as in the following example:

     TELNET>PAGE<RET>



2.11  CREATING A TELNET.CMD FILE

A TELNET.CMD file, which is automatically read when you invoke TELNET,
is  used  to  change  TELNET's  default  behavior.   If  you want your
terminal to have command characters from a previous version of TELNET,
you can place these commands in your TELNET.CMD file.

For example, if you want Y  for  the  intercept  character,  immediate
entry  into  EXTENDED  TALK  mode, and OPAQUE mode (see Section 2.10),
create a TELNET.CMD file that contains the following:

     ESCAPE 031 ;or a quoted control-y
     EXTENDED
     OPAQUE
     PAGE

To determine how to define a command in your TELNET.CMD file,  consult
the latest version of the TOPS-20 User's Guide.



2.12  CREATING A TELNET LOG FILE

To create a file that contains a transcript of  your  TELNET  session,
use the LOG command.  The command takes the form:

     LOG (FILE IS) log file name

Where log file name is the name you choose for your file.  The default
file name for a log file is TELNET.LOG.

TELNET's default is not to keep a log.  If you want to have a log, you
must  use  the  LOG  command.   Note  that  the  LOG command only logs
information from the foreign host.

A CLOSE command automatically closes  the  log  file.   However,  when
another connection is opened, the log file is reopened for append.

If you decide during your session that you no longer want a log  file,
you can use the NO LOG command.  To use this command, type:

     @TELNET>NO LOG<RET>

This closes your log file.

The following example shows the creation of a log file.

     @TELNET>LOG (FILE IS)TELNET.TXT <RET>
THE TELNET PROGRAM                                           Page 2-15


2.13  TAKING COMMANDS FROM FILES

TELNET accepts commands from specified input files by using  the  TAKE
command.  At the end of the file, TELNET reverts to accepting commands
from the  terminal.   In  addition,  TELNET  automatically  reads  the
TELNET.CMD file at start-up.

To use the TAKE command, type TAKE in response to the  TELNET  prompt,
followed  by  the  name of the input file from which you want commands
taken:

     TELNET>TAKE (Commands from file)input filespec <RET>

where input filespec is the name of the file that  you  want  commands
taken from.



2.14  TELNET MESSAGES

The most common TELNET messages, with their descriptions and suggested
user  responses,  are  listed  alphabetically  below.   Some  of these
messages are informational, describing  that  conditions  are  normal.
These messages merely confirm that TELNET is doing what you requested.
Other messages indicate an error at the remote site.  These errors are
not user errors.  The user has no control over them.

When TELNET is unable to continue with a user command, it outputs  one
of  the  error  messages  listed  below.   Generally, any TAKE file or
command that is in progress is  aborted.   These  errors  are  usually
errors  in  the  user's command line.  In the list below, fatal errors
are preceded by a question mark (?), and warning messages are preceded
by a percent sign (%).


?Abnormal fork termination interrupt

     TELNET's network input fork died involuntarily.   Because  TELNET
     is  supposed  to  check for all error conditions, this message is
     not expected to appear.

     SUGGESTED USER RESPONSE:  Contact the system people at your  site
     if this message appears on the terminal.

?Can't continue

     It is not possible to continue TELNET after a fatal error.

     SUGGESTED USER RESPONSE:  Restart the TELNET program.

?Character doesn't have a control form

     You gave the CONTROL command with an argument that cannot be made
     into a control character.
THE TELNET PROGRAM                                           Page 2-16


     SUGGESTED USER RESPONSE:  Respecify an argument that can be  made
     into a control character and issue the control command.

Connection Closed

     The user gave a CLOSE command.  TELNET is confirming that it  has
     closed the connection.

Connection closed by foreign host

     The remote host has closed the connection for  reasons  known  to
     itself, but not to TELNET.  For example, many hosts "hang up" the
     connection when you log out.  TELNET takes  the  same  action  it
     does when you give a CLOSE command.

Foreign host sent a subnegotiation

     The remote host is using the subnegotiation part  of  the  TELNET
     protocol.   Since TELNET does not allow subnegotiations, the host
     is violating protocol.  Some garbage  may  follow  this  message.
     This message is not expected to appear.

Insufficient system resources

     TOPS-20's network connection tables are full;  there is  no  room
     for a new connection.

     SUGGESTED USER RESPONSE:  Try connecting at a later time.

?Invalid ASCII value

     The number specified for the escape characters was not between  0
     and 177 octal.

     SUGGESTED USER RESPONSE:  Specify a  number  between  0  and  177
     octal.

?Invalid port number

     The number given was out of range for the named field.

     SUGGESTED USER RESPONSE:  Specify a number  that  is  within  the
     range of the named field.

?Log file error-...more details...

     TELNET was unable  to  reopen  the  log  file  when  opening  the
     connection.  The log file has been turned off, and the connection
     continues without it.

     SUGGESTED USER RESPONSE:  Correct the condition indicated in  the
     error  message,  and  reissue  a  LOG command if you still want a
     transcript of your session.

?...message...
THE TELNET PROGRAM                                           Page 2-17


     A miscellaneous nonfatal error occurred.  This is usually a  user
     error.

     SUGGESTED USER RESPONSE:  Correct the  error  and  try  the  task
     again.

?...message...,...instruction...at PC=...PC value...

     A fatal error has occurred.  The PC printed is  the  location  of
     the error.

     SUGGESTED USER RESPONSE:  Contact the system people at your  site
     if this problem occurs.

?Must have CONTROL-C capability to run TELNET

     The superior fork has  denied  TELNET  the  <CTRL/C>  capability,
     which  is  necessary  for  TELNET  to be able to trap a <CTRL/C>.
     TELNET needs the capability to perform properly.

     SUGGESTED USER RESPONSE:  This error message occurs if you try to
     run  TELNET  in  a  batch job.  Contact the system people at your
     site if this occurs and you are not using batch or have not given
     the SET NO CONTROL-C command to the EXEC.  Also, make sure not to
     run TELNET in batch.

?Not implemented with this protocol

     The  command  the  user  gave  is  meaningless  on  the   current
     connection  because  the  current  protocol  doesn't support that
     function.

     SUGGESTED USER RESPONSE:  Use a command that  is  implemented  by
     the protocol to which you are connected.

?No such host name-...more details...

     TELNET was expecting a host specification, but  the  input  given
     could not be interpreted.  Possibly a host name was misspelled.

     SUGGESTED USER RESPONSE:  Correct the error and try  the  command
     again.

?TAKE command in progress

     A command file run by the TAKE command tried to  execute  another
     TAKE.

     SUGGESTED USER RESPONSE:  Remove the second  and  any  additional
     TAKE commands from the TAKE file.

?Time out

     TELNET spent more than 30 seconds trying to do a  single  network
     output  operation.  TELNET assumes that the host at the other end
THE TELNET PROGRAM                                           Page 2-18


     is hung and aborts the connection.

     SUGGESTED USER RESPONSE:  Contact the system people at your  site
     or the remote site if this problem occurs repeatedly.

Trying...

     The user gave a CONNECT command, and TELNET is attempting to open
     the  connection.   TELNET  reports  the  result of the connection
     attempt with one of the following messages:

      o  Host dead...more details...- The remote host is not available
         at the present time.  If TELNET can get any details about the
         unavailability, it will report them.  This may  include  such
         things  as  a  message left by the remote host before it went
         down detailing why it went down and when it is expected to be
         up again.

      o  Insufficient system  resources-  TOPS-20  network  connection
         tables are full;  there is no room for a new connection.

      o  Open- TELNET has succeeded in opening  a  connection  to  the
         remote  host.   The next output on the terminal will probably
         be some greeting message from the remote host.

      o  Refused- The remote host is  up,  but  it  is  not  accepting
         connections  at  the present time.  This condition is usually
         temporary;  for example, the host might be momentarily unable
         to accept the connection.  Some hosts refuse connections when
         they  are  down  for  system  work.    TACs   always   refuse
         connections if you try to TELNET to them.

?Undefined error

     A  system  call  returned  an  error  number  that  is   not   in
     SYSTEM:ERRMES.BIN.

     SUGGESTED USER RESPONSE:  Contact the system people at your site.

?Unrecognized command-...more details...

     TELNET was expecting a command or  host  specification,  but  the
     input  given  could  not  be  interpreted  as either.  Possibly a
     command or host name was misspelled.

     SUGGESTED USER RESPONSE:  Correct the error in the  command  line
     and retry the command.











                              CHAPTER 3

                      THE FILE TRANSFER PROGRAM



3.1  INTRODUCTION

The ARPANET File Transfer Program (FTP) is a TOPS-20 function-oriented
protocol  that  is  used  to  transfer  files  between  ARPANET hosts.
Through controls and specifications, the FTP  protocol  establishes  a
common ground for file exchange and manipulation.

The FTP  protocol  uses  the  Transmission  Control  Protocol/Internet
Protocol  (TCP/IP)  to  establish a connection.  This connection sends
FTP commands from the  User-FTP  to  the  Server-FTP,  and  sends  FTP
replies  from the Server-FTP to the User-FTP.  The Server program also
establishes a  data  connection  for  transferring  data.   Thus,  two
connections are required:  one connection for commands and replies and
one connection for transferring data.  The data  connection,  however,
is transparent to the user.

The FTP protocol is implemented by two programs:  a User program and a
Server  program.   At  the  local  host,  you  interface  with the FTP
protocol through the User-FTP program.  At the remote  host,  you  are
dependent on the Server-FTP program.

The following diagram illustrates a user request for  a  file  at  the
remote site using the FTP protocol.



3.2  USING FTP

The User-FTP commands are the commands that you use at your  terminal.
These  FTP protocol commands handle communication between processes on
different hosts.  For this reason, FTP is more  transparent  and  less
user  interactive,  and  has  more  restrictions placed on the way the
program implements the protocol.

The recognition feature of TOPS-20 is  not  implemented  for  all  FTP
commands.   If  you press the escape (altmode) key after typing enough
letters to make a command unique, the bell sounds  if  recognition  is
not  implemented  with  the  command.  In this case, you must type the
full command.
THE FILE TRANSFER PROGRAM                                     Page 3-2


The FTP protocol may initiate transparent  Host-to-Host  interactions,
such   as  establishing  or  refusing  connections,  on  your  behalf.
Normally, you  do  not  need  to  know  that  these  transactions  are
occurring.   If you need to act, you receive a message indicating what
action you should take.

If you are a system  programmer,  you  should  be  familiar  with  the
RFC-765 ARPANET TCP/IP File Transfer Protocol Handbook and the TOPS-20
Monitor Calls User's Guide.

User-FTP commands can be classified into four categories:

      o  Controlling access to remote hosts

      o  Requesting a data transfer or remote file system service

      o  Controlling User-FTP locally

      o  Specifying data transfer parameters

Sections 3.3 through 3.6 of this manual describe these four categories
and the commands that implement the program.



3.3  RUNNING FTP

To gain access to the FTP program, type FTP in response to the TOPS-20
Exec  prompt.   You  are  then  prompted  with an asterisk (*).  The *
indicates that the FTP program is ready to accept commands.

To access a remote site and to  request  data  transfers  between  two
sites, you must also connect to the site and log in at the site.

The two commands used to perform these functions are:

      o  Connect

      o  Login


CONNECT COMMAND

The CONNECT command establishes the connection  to  the  remote  site.
The CONNECT command takes the form:

     CONNECT (to host)<host-name>
               or <decimal-byte>.<decimal-byte>.<decimal-byte>.
                  <decimal-byte>
               or  <octal-number>

where host-name is  the  official  host  name  or  the  official  host
nickname,  decimal-byte  refers  to a four-decimal octet INTERNET host
number, and octal-number refers to the host's octal number.
THE FILE TRANSFER PROGRAM                                     Page 3-3


The following example shows a completed FTP CONNECT command.

     *CONNECT (to host) DEC-MARLBORO <RET>

It is recommended  that  you  use  the  official  host  name  or  host
nickname.   If the host name or nickname is used, the User-FTP program
refers  to  a  table  of  Server  characteristics  to  establish   the
connection.   The  connection  parameters selected from this table are
specific and efficient.  If you use the host number, the User-FTP uses
whatever  parameters  were last used for a connection.  Therefore, you
may need to specify options.

If the CONNECT command is successful, you receive a message indicating
that  the connection has been established between the local and remote
sites.  This message is followed by the herald of the remote host.

The following example shows a CONNECT command followed by the response
of the remote host.

     @FTP
      *CONNECT (to host) DEC-MARLBORO <RET>
       Connection opened
       Assuming 36-bit connections, Paged transfers
      *<DEC-MARLBORO FTP Server Process 6(4)-7 at Thu 3-Mar-83 
         08:55-EST
      *

Once the connection has been established, you  are  dependent  on  the
Server-FTP  conventions.   Since  parameters  may  vary widely between
ARPANET hosts, you may have to use the *VERBOSE and *QUOTE commands to
help  you  at  first.   (These commands are discussed in Section 3.5.)
This should not normally be required.

If your FTP connection is not successful, you receive a  message  from
the  remote  host  indicating  the  reason.  You can either follow the
action indicated by the message for  that  remote  host,  or  you  can
attempt a connection to another FTP host.


LOGIN COMMAND

Having established a connection to a remote host, many  sites  require
that  you  log in at the remote host before attempting to accomplish a
data transfer.  The LOGIN command performs this function.

The LOGIN command takes the form:

     *LOGIN (user-ident) username (password)password (account)account

where user-ident or username is the name assigned for  your  login  at
the remote host, password is the password required by the remote host,
and account is the account required by the remote host.

Since you are dependent on the requirements of the remote host  during
login  at  the remote site, you must know the requirements of the host
THE FILE TRANSFER PROGRAM                                     Page 3-4


you are attempting to log in to.  All three  arguments  to  the  LOGIN
command  may  not be required, or they may be different arguments from
those required for login at the  local  host.   For  example,  TOPS-10
systems  require  project number and programmer number in the [n,m] as
the username parameter.  Some  hosts  require  a  previously  assigned
account  number  or  string;  some ignore the account parameter.  Most
remote hosts, however, do require that  the  LOGIN  command  be  given
immediately after a successful connection.

Documentation on login is available in the ARPANET Resource  Handbook.
If  you  require  additional help in securing FTP service, contact the
liaison officer for that site.  The ARPANET Resource Handbook contains
a list of liaison officers.

An example of a LOGIN command is given below.

     *LOGIN (user-ident) CPERLMAN (password)  (account)341 <RET>
     *<User CPERLMAN logged in at Thu 3-Mar-83 08:57-EST, job 13
     *



3.4  EXITING FTP

Three FTP Commands that are used to terminate an FTP connection are:

      o  BYE

      o  DISCONNECT

      o  QUIT OR EXIT

These commands determine whether your  FTP  connection  is  closed  or
maintained while you return to the local host.


BYE COMMAND

The BYE command terminates your access to the remote host  and  closes
your  connection  to the remote site.  The BYE command for the TOPS-20
FTP program  logs  out  your  job  at  the  remote  host,  closes  the
connection, and returns you to FTP command level.

The BYE command takes the form:

     BYE closes connection

There is no argument after the command.  Once the BYE command has been
executed,  you  receive  a  message indicating that the connection has
been terminated as in:

     *BYE <RET>
     *<QUIT command received.  Goodbye
     *
     -- Connection has terminated --
THE FILE TRANSFER PROGRAM                                     Page 3-5


     *


                                   NOTE

         If you give a second CONNECT command without executing  a
         BYE command, FTP responds with "closing first connection"
         before the new connection is opened.  Only one connection
         can be active at any one time.


DISCONNECT COMMAND

The DISCONNECT commands aborts the connection to the remote host.  The
DISCONNECT command takes the form:

     DISCONNECT from remote host (abort) <RET>

where a carriage return is used to confirm the command.  Following the
execution  of this command, you receive a message from the remote host
indicating  that  the  connection  has  been  aborted.    A   complete
DISCONNECT command, therefore, appears as:

     *DISCONNECT <RET>
     <QUIT command received. Goodbye.
     --Connection has terminated.--
     @


EXIT AND QUIT COMMANDS

The EXIT and QUIT commands allow you to return  to  the  TOPS-20  Exec
level  without  terminating the connection to the remote host.  To use
the EXIT and QUIT commands, type either EXIT or QUIT  in  response  to
the  FTP  prompt.   After  you  type  a carriage return, you receive a
message indicating that the connection is still open, followed by  the
TOPS-20 prompt (@).  You can then perform a task at the local host and
type CONTINUE to return to the FTP program.  An example of a completed
EXIT command follows.  The QUIT command takes the same format.

     *EXIT <RET>
     [The connection is still open.]
     @
     @CONTINUE <RET>
     *



3.5  GETTING HELP WITH FTP

The User-FTP program has a HELP command available to help you use FTP.
The  HELP  command  types information on commands, gives an example of
FTP usage, or types current status, according to your response to  the
HELP  command.   To use the HELP command, type HELP in response to the
FTP * prompt.  You are then prompted with:
THE FILE TRANSFER PROGRAM                                     Page 3-6


     *HELP <RET>
     C, E, S or ?

Your response to this prompt dictates what type of  help  you  receive
from the FTP program.

If you type C in response to the HELP command you are given a list  of
available  FTP commands.  The following example shows the use of the C
response to the *HELP command:

     *HELP <RET>
      C, E, S or ? C <RET>
      commands are:
     CONNECT to <host-name>
                or
     <decimal-byte>.<decimal-byte>.<decimal-byte>.<decimal-byte>
             or #<octal-number>
     LOGIN <username> <password> <optional-account>
     ACCOUNT <number> or <string>
     GET <remote-file> to <local-file>
     SEND <local-file> to <remote-file>
     MULTIPLE GET/SEND <local-file-group>
              Allows "*", TOPS20/TENEX sites only.
     APPEND <local-file> to <remote-file>
     RENAME <remote-file> to be <new-remote-file>
     DELETE <remote-file>
     DIRECTORY of <remote-user>
     CWD change working directory to <directory-path>
     STATUS of remote system
     BYE closes connection
     DISCONNECT from remote host (abort)
     EXIT returns to EXEC, without closing connection
     QUIT returns to EXEC, without closing connection
     MODE sets transmission mode to one of (S}
     STRUCTURE  sets structure of data to one of [F, P}
     TYPE sets data type to one of [A, N, I, L n}
     ASCII a shorthand for STRU
     PAGED a shorthand for STRU P, TYPE L 36
     TENEX a shorthand for TYPE I
     IMAGE a shorthand for TYPE I
     VERBOSE typeout mode
     BRIEF typeout mode
     QUOTE <arbitrary-FTP-line>
     STATISTICS turns on typeout of timing statistics
     NOSTATISTICS turns off typeout of timing statistics
     RETAIN turns on retention of generation numbers
     NO RETAIN turns off retention of generation numbers


     HELP types this information
     Type BELL (^G) to abort a file transfer and return to command
     level
     Type ^O to clear typeout buffer.
     Use ^V to quote characters in LOGIN.
THE FILE TRANSFER PROGRAM                                     Page 3-7


If you type E in response to the FTP HELP command, you  are  given  an
example of what an FTP connection is:

     *HELP
     C, E, S or ? E <RET>
     @FTP                               ;call in the subsystem
     *BBN                               ;connect to host BBN
     *LOG SMITH SECRET 12345            ;declare, name, password, account
                                        ;the password will not be echoed.
     *DIR *.MAC <RET>
     (to local file)TTY: [confirm]      ;get a partial directory 
                                         listing
     *GET PROGRAM.MAC <RET>             ;must end with carriage return
     (to local file)<esc>PROGRAM.MAC    ;escape causes the same name 
                                         to be used
     *BYE                               ;request server to terminate
     *QUIT
     @  

If you type the S response  to  the  HELP  command,  you  receive  the
current status of connections, as follows:

     *HELP
     C, E, S or ? S <RET>
     DEC-MARLBORO FTP User Process 6(13)-7
     The current data transfer parameters are:
          MODE S
          STRU P
          TYPE L 36
     NORETAIN generations
     A connection is open to host DEC-MARLBORO
     The data connection is closed.
     *

If you type the ?  in response to the  HELP  command,  you  receive  a
message  indicating  which  of  the  responses you should make to this
command:

     *HELP <RET>
     C, E, S or ? ? <RET>
     Type "C" for a list of commands, "E" for an example of FTP use,
     or "S" for current status.
     C, E, S or ?
     ? Type "HELP<RETURN>" for help.

Three other FTP commands are useful  in  getting  help  in  using  the
User-FTP  program.  These commands, VERBOSE, BRIEF, and QUOTE, provide
more information on user  input  required  to  accomplish  FTP  tasks.
These commands are discussed below.


VERBOSE COMMAND

The VERBOSE command causes additional  informational  messages  to  be
displayed  on  your  terminal.   These  messages,  which  are  usually
THE FILE TRANSFER PROGRAM                                     Page 3-8


transparent during your FTP session, are  the  User-FTP  commands  and
Server-FTP    replies.    Included   in   these   messages   are   the
response-coding numbers.  The FTP response-coding system is  discussed
in Section 3.7.1.  The VERBOSE command takes the form:

     VERBOSE <RET>

where a carriage return is used to confirm  the  command.   Once  this
command  is  executed,  you  receive  additional  information  at your
terminal.

The VERBOSE command is typed prior to the command for which additional
information  is  required.   The command is especially useful when you
are unfamiliar with a command that you want to use.  It is also useful
when attempting a connection to a remote host whose procedures you are
unfamiliar with.  In this case, type VERBOSE prior  to  attempting  to
log in to the host.

An example of the VERBOSE command follows:

     *VERBOSE <RET>
     *CONNECT (to host) DEC-MARLBORO <RET>
      Connection opened.
      Assuming 36-bit connections, Paged transfers.
     *<220 DEC-MARLBORO FTP Server Process 6(4)-7 at Thu 3-Mar-83
       09:31-EST
     *LOGIN (user-ident) CPERLMAN (password)  (account)
     *<331 User name ok. Password, please.
     *<230 User CPERLMAN logged in at Thurs 3-Mar-83 09:31-EST, job 19.
     *


BRIEF COMMAND

The BRIEF command, which is  the  FTP  default,  cancels  the  VERBOSE
command.   There  is  no  argument  for  this  command.  Once you have
received the information you  require  through  the  VERBOSE  command,
typing  BRIEF  cancels  the display of the additional information.  To
use the BRIEF command, type:

     *BRIEF <RET>

where the carriage return is used to confirm the command.


QUOTE COMMAND

The QUOTE command is used to send information to the remote host  with
no  translation  by the FTP program.  The text is sent directly to the
Server.  To use the QUOTE command, type QUOTE  followed  by  a  space,
followed  by whatever information you wish the remote host to receive.
When you press the carriage return, this information is  sent  exactly
and  directly to the remote host.  The FTP protocol does not interpret
this information.
THE FILE TRANSFER PROGRAM                                     Page 3-9


In the following example, a user has requested a  new  password  using
the  CWD  command.   (See  Section 3.6.1 for a discussion of CWD.) The
user wants to send this password directly to  the  remote  host.   The
command, therefore, appears as:

     *QUOTE PASS DEC-20 <RET>

The QUOTE command causes the string "pass DEC-20" to be sent  directly
to the remote host.



3.6  FTP COMMANDS

The following sections discuss the FTP commands used to:  request data
transfers  or  remote  file system service, get local information, and
specify the data transfer parameters.



3.6.1  Requesting Data Transfers or Remote File System Service

Some FTP commands are used to request a service from the remote  host.
Included  are  commands  that  request files to be moved, deleted, and
renamed.  The requests that are made  must  conform  to  the  User-FTP
requirements.   If defaults are allowed, they are Server defaults.  If
a name is used for a device or file presently located or to be located
at   the   remote   site,  the  name  follows  the  Server-FTP  naming
conventions.

You cannot give any commands during a file transfer.   You  must  wait
for  the  *  prompt  following the transfer complete message.  You can
type <CTRL/G>, however, if you want to abort the transfer.


                                 NOTE

               Some Servers are  able  to  monitor  the
               command    connection    (commands   and
               responses) and the data connection (file
               transfers) simultaneously.  Consult your
               System Manager before attempting to  use
               this feature.


The following sections discuss the FTP Service commands.


GET COMMAND

The GET Command is used to request that a copy of a file at the remote
site  be  transferred  to  a  file at the local site.  The GET command
takes the form:

     GET (foreign-filename) filename 1 <RET>
THE FILE TRANSFER PROGRAM                                    Page 3-10


      to (local-file) filename 2 <RET>

where filename 1 is the name of the remote file you are requesting and
filename  2 is the name of the local file.  Filename 1 uses the naming
conventions of the  remote  host,  and  filename  2  uses  the  naming
conventions  of the local host.  It is recommended that you always use
a complete file specification for the local file.

If you do not type a directory name  preceding  either  file  name,  a
default  is  used.   For the remote file, the default directory is the
FTP-login directory.  Or, if a CWD (Change Working Directory)  command
has  been  given (see discussion of CWD below), the directory named in
the CWD command is the default.   For  the  local  file,  the  default
directory is your current connected directory.  If you press the <ESC>
key for the local file, the exact name string used in the remote  file
name is used for the local file name.

When a GET command has been executed, you receive a message indicating
that the transfer has begun.  A second message appears indicating that
the transfer has been completed.  If the transfer cannot be completed,
you   receive   a   message  indicating  this.   You  can  follow  the
instructions in this message to correct the problem and  then  reissue
the *GET command.

The following example shows a completed GET command:

     *GET (foreign-filename) TELNET.LOG.3 <RET>
          (To local-file)TELNET.LOG.3 <RET>
     <PAGED retrieve of <CPERLMAN> TELNET.LOG.3 started
     <Transfer completed.
     *


SEND COMMAND

The SEND command is used to transfer a copy of a file from  the  local
host to the remote host.  The SEND command takes the form:

     SEND (local-file) filename1 <RET>
          (to remote-file) filename2 <RET>

where filename 1 is the name of the local file, and filename 2 is  the
name of the remote file.

The same naming conventions  and  messages  that  apply  to  the  SEND
command apply to the GET command.

An example of the SEND command follows:

     *SEND (local-file) TELNET.LOG.5 <RET>
           (to remote-file)TELNET.LOG.5 <RET>
     <Paged store of <CPERLMAN> TELNET.LOG.5; P777700; A341 started.
     <Transfer completed.
     *
THE FILE TRANSFER PROGRAM                                    Page 3-11


MULTIPLE GET/SEND COMMANDS

TOPS-20  ARPANET  sites  allow  MULTIPLE  GET/SEND  commands.    These
commands  allow  the  use  of  the  TOPS-20  wildcard  feature for the
transfer of multiple files either to or from a remote host.

The MULTIPLE GET/SEND commands take the form:

     MULTIPLE GET (remote-file group) group filename 
       or extension <RET>
               or
     MULTIPLE SEND (local-file group) group filename 
       or extension <RET>

where in either command a wildcard can be used for the file  names  or
the extensions, as in:

     *MULTIPLE GET (remote-file group) FTP.* <RET>
               or
     *MULTIPLE SEND (local-file group) *.MEM <RET>

All other naming conventions and defaults that apply to  the  GET  and
SEND commands apply to the MULTIPLE GET/SEND commands.

An example of a MULTIPLE GET command follows:

     *MULTIPLE GET (remote-file group) *.MEM <RET>
     <List started.
     <Transfer completed.
     ARPA.MEM.4
     <Paged retrieve of <CPERLMAN> ARPA.MEM.3 started.
     <Transfer completed.
     <SAMPLE.MEM.13
     .
     .
     .
     *


RENAME COMMAND

The RENAME command is used to rename a file at the remote  host.   The
RENAME command takes the form:

     RENAME (existing-file) filename 1 <RET>
              (to be) remote-filename <RET>

where filename 1 is the current name of the  remote  file  and  remote
filename  is  the new file name for the file.  File-naming conventions
follow the requirements of the remote host.

An example of the RENAME command follows:

     *RENAME (existing-file) ARPA.MEM.4 <RET>
              (to be) ARPA.TXT.1 <RET>
THE FILE TRANSFER PROGRAM                                    Page 3-12


     <Old file renamed <CPERLMAN> ARPA.TXT.1
     *


DELETE COMMAND

The DELETE command is used to delete files at the  remote  host.   The
command takes the form:

     DELETE (foreign file) filename <RET>

where filename is the name of the file you want to have deleted.

When you have issued a DELETE command, you are asked whether  this  is
the  file  you want to delete.  This is done to insure that you do not
delete the wrong file.  If you make a mistake in typing the file name,
you  can  edit the file name before pressing the <RET> key.  If you do
not want to delete the file, answer N in response to the message.  You
then see the FTP prompt.

An example of the DELETE command follows:

     *DELETE (foreign file) FTP.LOG.2 <RET>
     Do you really want to delete FTP.LOG.2 (Y or N)? Y <RET>
     *<Lowest generation deleted ok, file <CPERLMAN> FTP.LOG.2
     *


CWD COMMAND

The CWD (Change Working Directory) command is used  either  to  change
your default directory at the remote site or to connect to a different
directory at the remote site.  This command is similar  to  a  TOPS-20
Connect  command.  Access to a different directory for file storage or
retrieval at the remote site  is  possible  with  this  command.   The
command takes the form:

     CWD (to directory) directory name <RET>

where directory name is the name to be given to the working  directory
or the name of the directory you want to access.

This command saves the overhead of repeating the log-in and accounting
information.   Transfer parameters remain as originally selected.  The
name given for the directory follows  the  convention  of  the  remote
host.   Also,  the remote host may require that you type a password or
account at this time.  The TOPS-20 Server-FTP  program  requires  that
you  give a password if you are required to give a password when doing
a connect to the named directory.

An example of the CWD command follows:

     *CWD PS:<PAETZOLD> <RET>
     *<250 Connected to PS:<PAETZOLD>.
THE FILE TRANSFER PROGRAM                                    Page 3-13


                                 NOTE

               TOPS-20     directory     format      is
               STRUCTURE:<DIRECTORY>  where  STRUCTURE,
               if  not  specified,  defaults   to   the
               current    connected    structure    and
               <DIRECTORY>, if not specified,  defaults
               to the current connected directory.

               TENEX  and   several   other   operating
               systems   use  the  format  USERNAME  or
               username for directory.


DIRECTORY COMMAND

The DIRECTORY command is used to request that a listing of  the  names
of  the files in the named directory at the remote host be sent to the
local host.  The DIRECTORY command takes the form:

     DIRECTORY (of remote user) DIRECTORY NAME <RET>
      to local file: filename or TTY: <RET>

where DIRECTORY NAME is the name of  the  remote  directory  you  want
listed,  filename  is  the name of the local file you want to have the
directory placed in, and TTY:  is used to have the directory output to
your terminal.

You must type TTY:  if you want output to your terminal.   File-naming
conventions  follow  the  local  host requirements if you want to have
output placed in a file.  If you do not type  a  directory  name,  the
default argument is your current connected directory.

You receive a message indicating that the transfer has been completed.

An example of the DIRECTORY command follows:

     *DIRECTORY of <CROSSLAND> <RET>
     to local-file: TTY: <RET>
     <List started.
     PS:<CROSSLAND>
     CHING.MAC.4
     DUMMY.1
     MAIL.TXT.1
     TEMP.FIL.1
     <Transfer completed.
     *


STATUS COMMAND

The STATUS command is used to request information about the parameters
of  your  current  connection  to the remote host.  The STATUS command
takes the form:
THE FILE TRANSFER PROGRAM                                    Page 3-14


     STATUS (of server) <RET>

where a carriage return <RET> is used to  confirm  the  command.   You
then  receive  a  message  that  shows the current parameters for your
connection, as follows:

     *STATUS <RET>
     DEC-MARLBORO FTP User Process 6(13)-7
     The current data transfer parameters are:
          MODE S
          STRU P
          TYPE L 36
     NORETAIN generations
     A connection is open to host DEC-MARLBORO
     The data connection is closed.
     *


ACCOUNT COMMAND

The ACCOUNT command takes the form of:

     ACCOUNT <number> or <string> <RET>

The ACCOUNT command accepts  either  a  number  or  a  string  as  the
argument  identifying  the  user's  account  at the remote site.  This
command is not necessarily related to the  account  parameter  in  the
LOGIN  command.  Some hosts require that an account be given to access
specific files, or to manipulate files in a specific way.  The ACCOUNT
command is provided to satisfy this requirement.


RETAIN COMMAND

The RETAIN command causes the  generation  number  of  a  file  to  be
transferred either to or from a remote host.  The generation number of
the file is not changed by the FTP protocol during transmission.   The
RETAIN command takes the form:

     RETAIN <RET>

where a carriage return is used to confirm  the  command.   Once  this
command  is  executed, generation numbers are sent/received exactly as
they appear in the name string.


NORETAIN COMMAND

The NORETAIN command, which is the system default, cancels the  RETAIN
command.  This command takes the form:

     NORETAIN <RET>

where a carriage return is used to  confirm  the  command.   Once  the
NORETAIN  command  is executed, generation numbers of files can change
THE FILE TRANSFER PROGRAM                                    Page 3-15


during transmission.  Therefore, if there is a  file  being  requested
that has a generation number of 4 and there is no existing file at the
receiving site, the file will have a generation number of 1 when it is
received, as follows:

     *GET (foreign-filename) TELNET.TXT.4 <RET>
          (to local-file) <ESC> TELNET.TXT.1 <RET>

If the NORETAIN command is executed,  you  must  type  the  generation
number if you want to have the generation number retained.



3.6.2  FTP Information Commands

In addition to the VERBOSE and QUOTE  commands  already  discussed  in
Section  2.5,  another  command,  the  STATISTICS  command,  is passed
directly to the program.  Neither the command connection nor the  data
connection  are  involved.   All  communication is accomplished at the
local site.


[NO]STATISTICS COMMAND

The STATISTICS command and its counterpart, the NOSTATISTICS  command,
are  used  to  control the terminal display of statistical information
about a transfer.  The information you receive displays statistics  on
file transfer rate, bits sent, and time consumed during data transfer.
This information  is  displayed  after  the  data  transfer  has  been
completed.

The STATISTICS command takes the form:

     STATISTICS <RET>

where a carriage return <RET> is used to confirm the  command.   There
is  no  argument  to  the  command.   The  STATISTICS command is typed
immediately prior to the command for  which  you  are  requesting  the
statistical information.

An example of the STATISTICS command follows:

     *STATISTICS <RET>
     *GET (foreign-filename) TELNET.LOG.2 <RET>
          (to local-file) TELNET.LOG <RET>
     <Paged retrieve of <CPERLMAN> TELNET.LOG.5 started.
     <Transfer completed.


     137. bytes transferred, run time = 96. MS,
     Elapsed time =3080. MS, Rate =1601. Baud
     *

The NOSTATISTICS command cancels the STATISTICS command.  There are no
arguments  to  the  NOSTATISTICS command.  The NOSTATISTICS command is
THE FILE TRANSFER PROGRAM                                    Page 3-16


the system default.  Therefore, the NOSTATISTICS command is only  used
if you want to cancel a STATISTICS command.

The NOSTATISTICS command takes the form:

     NOSTATISTICS <RET>

where a carriage return is used to confirm the command.



3.6.3  Controlling FTP Transfer Parameters

FTP transfer parameters specify how bits are transmitted and  how  the
data  is represented.  You seldom need to use these parameter commands
since the User-FTP protocol selects those parameters that provide  the
best  fit  for  a  connection before attempting a connection.  This is
done transparently.   All  but  a  few  hosts  accept  the  parameters
selected by the program.

If you give a data transfer parameter command that  is  known  by  the
program to be "unsuitable," the command is ignored.  If you are trying
to receive service from a host and the host  is  either  unwilling  or
unable  to  accept  the  existing data transfer parameters, the remote
host generally sends you a message indicating that  the  parameter  is
not  supported.   If this happens, it is recommended that you try some
other combination of parameter values.  If it is  important  that  you
receive  some  service  from  that particular host, contact the System
Manager or the liaison contact for that site.


                               WARNING

               If you need  to  use  the  FTP  transfer
               parameter  commands,  contact  a  system
               person at your site.  Do not attempt  to
               use   these  commands  if  you  are  not
               experienced with them.


All  hosts  in  the  FTP  program  must  accept  a  set  of   "minimum
implementation"  values  for data transfer parameters.  All FTP hosts,
therefore, accept the following values as standard defaults:

     TYPE:  ASCII NONPRINT
     BYTE:  8 bits
     MODE:  STREAM
     STRU:  FILE

These four default values are implemented in the TOPS-20 FTP programs.
The  default  values  are assumed unless the user or, more frequently,
the User-FTP program gives  a  command  with  different  values.   The
transfer values set are normally reported in a message.

The data transfer commands  supported  by  the  User-FTP  program  are
THE FILE TRANSFER PROGRAM                                    Page 3-17


discussed below.


TYPE COMMAND

The TYPE command specifies the  data  representation  type.   Possible
arguments are A, I, and L.  The TYPE command takes the form:

     TYPE (key letter) letter (decimal) number <RET>

where key letter can be A, I, or L and number is 8, 32, or 36.

TYPE  A  specifies  NVT-ASCII,  that   is   a   7-bit   ASCII   string
right-justified  in  an 8-bit byte with no vertical format information
for printing.  TYPE I (Image)  specifies  contiguous  bits  that,  for
transfer,  are  packed  into  bytes  of the size specified in the BYTE
command.  Type L (Long) specifies a logical byte size.  Theoretically,
the  logical  byte  size  and  the data transfer byte size may differ.
Because of the restrictions described, and because the  byte  size  is
taken  from the BYTE command (explicit or implied), the TYPE L command
is seldom used.

An example of the TYPE command follows:

     TYPE (key letter) L (decimal) 36 <RET>


STRUCTURE COMMAND

The STRUCTURE command specifies the file structure to  be  used.   FTP
currently  recognizes file structure and paged structure.  The TOPS-20
user-FTP program selects a default structure  based  on  the  type  of
operating  system at the remote site.  If the remote site is listed as
TOPS-20, TOPS-10, or TENEX, PAGED structure is used  as  the  default.
Other systems use FILE structure as the default.

The STRUCTURE command takes the form:

     STRUCTURE (key letter) letter <RET>

where letter is either P for page structure, F for file structure,  or
R for record structure.

An example of the STRUCTURE command follows:

     *STRUCTURE (key letter) F <RET>


MODE COMMAND

Only the stream transfer mode is supported by TOPS-20.   This  is  the
default  mode.   If the MODE command is given, the argument must be S.
The  FTP  protocol  also  recognizes   block   and   compressed   mode
(represented  as  B  and  C,  respectively).   B  and  C modes are not
supported by TOPS-20.  Since  all  FTP  implementations  must  support
THE FILE TRANSFER PROGRAM                                    Page 3-18


stream mode, there should be no problem.

The MODE command takes the form:

     MODE (key letter) letter <RET>

where the letter for TOPS-20 is S.  An example  of  a  completed  MODE
command follows:

     *MODE (key letter) S <RET>



3.7  RESPONSE CODES AND MESSAGES

The FTP protocol specifies that  each  command  received  by  the  FTP
Server  generate  at least one reply.  Thus, the User process is aware
of the current state of the Server whether the command  is  successful
or   unsuccessful.   There  is  currently  one  exception.   Before  a
connection is made, any error in the CONNECT command itself results in
the ?  response rather than a meaningful message.  Once the connection
is established, you generally receive sufficient response to  commands
to permit you to continue.

A 3-digit numbering system is followed for all response codes.   These
codes are for the User-FTP program and are interpreted by the program.
The program may or may not verbalize the implied content of  the  code
and  display  it  for the user.  If you use the VERBOSE command, reply
codes with explanatory verbal messages are displayed on your terminal.
Use  of the VERBOSE command is recommended whenever you are engaged in
unfamiliar tasks or are connecting to a host  whose  operating  system
you are not familiar with.

Command responses that appear on your terminal may originate in either
the  User-  or  Server-FTP  program.   Messages  from  the  server are
preceded by a left angle bracket (<).  The  content  of  responses  is
specified,  but the specific wording is left to the implementing site.
Because you may be connecting to many different  Servers,  it  is  not
possible  to list all possible responses.  There are varying texts for
the same reply code.

Server-FTP responses may sometimes appear on your terminal  while  you
are  typing  commands to the User-FTP.  The * prompt may appear before
the response to the previous command.

If you have any problems with coded responses from a  Server,  contact
the  liaison  person  at  the  Server  site.   See the current ARPANET
RESOURCE HANDBOOK for both a list of liaison contact and  instructions
on  getting an up-to-date list by means of the ARPANET.  Such problems
as replies not clearly worded, replies that do not appear  appropriate
in  the  context  of  the  existing connection, or negative completion
replies  that  you  cannot  understand  should  be  reported  to   the
appropriate Server site.
THE FILE TRANSFER PROGRAM                                    Page 3-19


3.7.1  Response-Coding System

The major category of the response code  is  specified  by  the  first
digit.  This digit indicates the general acceptability of the command.
The second digit distinguishes the first digit by  function,  and  the
third digit distinguishes the second.

The first digit indicates acceptability as follows:


     1nn Positive Preliminary Reply.

          An action has been requested and has  been  started;   there
          will be another reply before the next command is considered.

          Example:  150  file  status  okay;   about  to   open   data
          connection.


     2nn Positive Completion Reply.

          An action has been  requested  and  completed  successfully.
          The next command can be given.

          Examples:  212 Directory status.
                     250 Requested file action okay, completed.


     3nn Positive Intermediate Reply.

          A command has been given and accepted, but more  information
          is  required.  This is used specifically in command sequence
          groups.

          Example:  332 Log in first, please.


     4nn Transient Negative Completion Reply.

          This reply encourages you to try again.   Your  command  was
          received  and  no action was taken.  The error condition can
          be corrected without changing the  command,  the  arguments,
          the  file  access,  or  the  username, and without requiring
          additional implementation on the part of  the  Server.   You
          are  most  likely  to  get  this  reply  code when there are
          problems not associated with errors in the commands.

          Examples:  421 Service not available closing connection.
                     This is given in reply to any  command  when  the
                     server knows the system is going down.
                     452 Requested  action  not  taken:   insufficient
                     storage space in system.


     5nn Permanent Negative Completion Reply.
THE FILE TRANSFER PROGRAM                                    Page 3-20


          A command was given but it was not  acceptable.   No  action
          was  taken.   A  reply  with  5  as  the  first digit always
          indicates an error.  The user must decide  from  the  verbal
          message  what  action should be taken.  Read the message and
          then examine the command  that  caused  the  message  to  be
          given.   Perhaps  a  change in spelling or in your connected
          directory is in order.  Perhaps the remote system is using a
          file  you  have  requested.   If  so,  give the BYE and QUIT
          commands and return later.  However, if the  verbal  message
          indicates  the command is not implemented, no further action
          is possible.

          Examples:  501 Syntax error in parameters or arguments.
                     502 Command not implemented.
                     550 Requested action not taken: file unavailable.

The second digit is based on a functional classification as follows:

     n0n Syntax, including syntax errors or unnecessary commands

     n1n Information

     n2n Connections

     n3n Authentication (logon) and Accounting

     n4n Reserved

     n5n File system

The third digit further defines the meaning  assigned  in  the  second
digit.   Hosts  adding to or implementing an FTP program are requested
to adapt the verbal expression for a reply code if an already  similar
3-digit code exists.  An example of the function of the third digit is
found in  the  21n  series.   All  four  replies  below  are  positive
completion;   all  are information replies.  The third digit indicates
the type of information.

     211 System status or system help
     212 Directory status
     213 File status
     214 Help message











                              CHAPTER 4

                                TSTATS



4.1  INTRODUCTION

TSTATS  is  an  ARPANET  utility  that  provides   information   about
connections   between   hosts.    TSTATS   gives   you  the  following
information:

      o  The existing connections

      o  The state of the connections

      o  The number of bytes of data you can send to a receiving host



4.2  RUNNING TSTATS

To run TSTATS, type TSTATS in response to the command level prompt, as
in the following example:

     @TSTATS <RET>

When you press carriage  return,  a  statistical  listing  of  ARPANET
connections is displayed on your terminal.

The following example shows the information displayed in  response  to
the TSTATS command.

@TSTATS <RET>
JFN       STATE       LPORT  FPORT  FGN-HOST    R-SEQUENCE  S-SEQUENCE  SENDW
1,2   FIN.FIN.--P----    25      0  0,0,0,0              0           0      0
0,2   -3-.EST.0-PAV--    23  13591  RADC-TAC    1780306709   359662611    256
0,4   -3-.EST.O-PAV--    23   6679  RADC-TAC    1791488463  3027243164    256
0,5   -3-.EST.0-PAV--    23   4582  DEC-MARLBORO3056730154  3066953916    777
0,1   FIN.FIN.--P-V--    23      0  0,0,0,0              0           0      0
1,1   FIN.FIN.--P----    21      0  0,0,0,0              0           0      0
@

Once this information is displayed on your terminal, you are  returned
to  command  level.   The  TSTATS  utility  has  no  other commands or
arguments.
TSTATS                                                        Page 4-2


4.3  INTERPRETING TSTATS

This section discusses the information displayed by TSTATS.


JOB NUMBER, JFN

The first column in TSTATS lists the job number for your job  and  the
job file number (JFN) within the job.  In the example presented above,
the numbers 1,2 under JFN represent job number 1 and job  file  number
2.


STATE

The second column in TSTATS lists the state of the connection for  the
local  port  and  the foreign port.  The first code word indicates the
state of the local port.  The second code word indicates the state  of
the  foreign  port.  The code words that are printed are states caused
by the TSTATS protocol.  The  letters,  called  flags,  represent  the
states  caused  by  what  the user requests.  Both words and flags are
displayed in the STATE column.

Connections can be in one of the following states:

     CODE      MEANING

     EST       Established
     PND       Pending
     SYN       Opened by one host
     FIN       Closed by one host
     NOT       Closed by both host
     O         Connection open
     P         Push (to send information)
     A         Connection aborted
     V         Send sequence number is valid
     U         Urgent data to be received

An established connection (EST) is an active  connection  between  two
hosts.   A pending connection (PND) exists when one host has requested
a connection (SYN) and is waiting  for  the  other  host  to  indicate
whether  or  not  the  host  will  accept  the  connection.   A closed
connection (NOT) exists when both hosts have closed the connection.  A
NOT  connection may also exist when a local host has never established
a connection and is  open  or  listening  for  a  connection.   A  FIN
connection  exists  when  one  host  has  closed the connection and is
waiting for the other host to close the connection.

An O flag is displayed when an active connection exists.  A  P  (PUSH)
flag  is  displayed  when  the user has issued a command that requires
immediate  delivery  of  data.   An  A  flag  is  displayed  when  the
connection  has  been  aborted.   A  V flag is displayed when the send
sequence number (see discussion of sequence number below) is valid.  A
U  flag  is displayed when there is a high-priority message, such as a
TELNET control message, to be sent to the local host.   This  priority
TSTATS                                                        Page 4-3


message takes precedence over all other data.

In the following example of a STATE column, both hosts are waiting for
the  connection to be closed.  The FIN.FIN indicates this.  The P flag
indicates that data has been sent and is guaranteed delivery.

         STATE
     FIN.FIN.--P----


LOCAL PORT, FOREIGN PORT

The third and fourth  columns  in  TSTATS  list  the  ports  that  the
connections exist on.  TCP/IP establishes connections between hosts on
specific ports.  Ports indicate the type of connection.  Ports may  be
TELNET,  FTP,  or  mail.   (For  a  detailed  discussion of ports, see
Chapter 2, TELNET.) The third column of TSTATS lists  the  local  port
(LP) or the connection on the local host side.

In the following example, a TELNET connection  exists  for  the  local
port.  This is indicated by the number 23.

     LPORT
        23

The fourth column of  TSTATS  lists  the  foreign  port  (FP)  or  the
connection  on  the  foreign side.  The ports for the foreign port are
given as decimal numbers.

The most common ports are:

     Port 21    FTP
     Port 23    TELNET
     Port 25    Mail

A port designated as  0  indicates  that  a  host  is  waiting  for  a
connection.


FOREIGN HOST (FGN-HOST)

The fifth column, FGN-HOST, lists the host name for the  foreign  host
side  of the particular connection.  Most often, this column lists the
host name.  If the host name is unknown, the decimal octet  number  of
the host is displayed.  If zeros (0) are displayed in the foreign host
column, there is no connection to a foreign host.

In the following example, the first foreign  host  has  zeros  listed.
This  indicates  that  no connection exists.  In the second line under
the header, the name RADC-TAC is  listed.   This  indicates  that  the
foreign host is RADC-TAC.

     FGN-HOST
     0,0,0,0
     RADC-TAC
TSTATS                                                        Page 4-4


RECEIVE SEQUENCE (R-SEQUENCE)

The sixth column in TSTATS lists the  receive  sequence  (R-SEQUENCE).
The  receive  sequence is the number of the next byte that the foreign
port will receive.

In the following example, the receive sequence is 1780306709.

     R-SEQUENCE
     1780306709


SEND SEQUENCE (S-SEQUENCE)

The seventh column in TSTATS lists  the  send  sequence  (S-SEQUENCE).
The  send  sequence is the number of the last byte that the local host
sent to the foreign host.

In the following example, the send sequence is 359662611.

     S-SEQUENCE 359662611


SEND WINDOW (SENDW)

The final column in TSTATS is  the  send  window  (SENDW).   The  send
window in TSTATS is the number of bytes of data that a foreign port is
either willing or able to receive from the local  port.   Most  often,
the  send  window  is  determined by the buffer space available at the
foreign host.  If the SENDW is at 0, the foreign port will not  accept
data  transmission.   The SENDW does change as space becomes available
or unavailable.

In the following example, there is a send  window  of  0  and  a  send
window  of  256.  The send window of 0 indicates that the foreign port
is unwilling or unable  to  accept  data.   The  send  window  of  256
indicates that the foreign port is able or willing to accept 256 bytes
of data.

     SENDW
         0
       256











                              CHAPTER 5

                                IPHOST



5.1  INTRODUCTION

IPHOST is an ARPANET utility that:

      o  Gives information about ARPANET hosts.

      o  Converts host numbers from one format to other formats.

      o  Cycles the ARPANET up and down.



5.2  RUNNING IPHOST

To run IPHOST, type IPHOST in response to the TOPS-20 prompt.  You are
then  prompted  with  IPHOST followed by a right angle bracket (>), as
in:

     @IPHOST <RET>
     IPHOST- TOPS-20 TCP/IP Host Utility Program - Version 6(25)
     IPHOST>

At this point, the IPHOST program is ready to accept commands.



5.3  EXITING IPHOST

To exit from IPHOST, type EXIT in response to the  IPHOST  prompt,  as
in:

     IPHOST> EXIT <RET>
     @

You are then returned to the Exec command level.
IPHOST                                                        Page 5-2


5.4  GETTING HELP WITH IPHOST

The two commands used to get help with IPHOST are  the  question  mark
(?) and the HELP command.

The question mark typed after the IPHOST prompt gives a  list  of  the
IPHOST  commands.  The following example shows the use of the question
mark:

     IPHOST>? one of the following:
      ARPANET    CONVERT    EXIT    HELP    LOCAL    NAME    NUMBER

Escape can be used to help complete command strings.   In  this  case,
type  an <ESC> following the command.  The IPHOST program then prompts
you for the information needed to complete  the  command,  as  in  the
following example:

     IPHOST>NAME (OF HOST IS)DEC-MARLBORO ?  confirm with carriage return

The HELP command prints a brief  help  text  at  your  terminal.   The
following  example  shows  the  text  printed  in response to the HELP
command.

     IPHOST> HELP <RET>
     Command         Description
     ---------------------------------------------------------------
     ARPANET         Arpanet interface control functions.
     CONVERT         Convert host numbers from one format to the 
                     other formats.
     EXIT            Return to EXEC level
     HELP            Type this text.
     LOCAL           Dump information about the local host.
     NAME            Dump information about a specific host given
                     the name.
     NUMBER          Dump information about a specific host given 
                     the number.  The number is in the 
                     format aaa.bbb.ccc.ddd.



5.5  IPHOST COMMANDS

IPHOST commands fall into three categories:

      o  Commands that give information about ARPANET hosts.

      o  Commands that convert decimal, octal, and INTERNET numbers to
         other formats.

      o  Commands that cycle the ARPANET up and down.

The following section discusses the IPHOST commands.


NAME COMMAND
IPHOST                                                        Page 5-3


The  NAME  command  gives  information  about  ARPANET   hosts.    The
information  includes  decimal octet number, host name, status as user
or server, and type of software.  The NAME command takes the form:

     IPHOST>NAME (OF HOST IS) host name <RET>

where host name is either the host name or host nickname.  If you  are
unsure  of the host name or nickname, typing a question mark after the
NAME command displays  a  list  of  server  host  names,  server  host
nicknames,  user  host  names, and user host nicknames.  The following
example shows the information displayed in response  to  the  question
mark after the NAME command:

     IPHOST>NAME (OF HOST IS) ? <RET>


     Server Host Name
     ----------------
     One of the following:
     ACC          ADA-VAX          AEROSPACE          AFGL
     AFSC-AD      AFSC-DEV         AFSC-HG            AFSC-SD
     AFWL         AMES-11          AMES-67            ANL
     ANL-MCS      ARPA-DMS         BBN-CLXX           BBN-INOC
     .
     .
     .

The following example shows the information displayed in  response  to
the NAME command.

     IPHOST> NAME (OF HOST IS) DEC-MARLBORO <RET>
      010.001.000.079 DEC-MARLBORO, SERVER, USER, TOPS-20


LOCAL COMMAND

The LOCAL command provides the same information for the local host  as
the  NAME  command  provides  for a specified host.  The LOCAL command
takes the form:

     IPHOST>LOCAL (HOST INFORMATION) <RET>

Following a carriage return, the information shown  in  the  following
example is displayed at your terminal:

     IPHOST>LOCAL (HOST INFORMATION) <RET>
      010.001.000.079 DEC-MARLBORO, SERVER, USER, TOPS-20


NUMBER COMMAND

The NUMBER command gives the same information as the  NAME  and  LOCAL
commands,  but you input a host decimal octet number instead of a host
name.  The NUMBER command takes the form:
IPHOST                                                        Page 5-4


     IPHOST>NUMBER (OF HOST)DECIMAL OCTET <RET>

where decimal number is one of the decimal  octets  for  the  INTERNET
host  you  want  information  about.   The following example shows the
information displayed with the NUMBER command.

     IPHOST>NUMBER (OF HOST) 10.1.0.79 <RET>
      010.001.000.079 DEC-MARLBORO, SERVER, USER, TOPS-20


CONVERT COMMAND

The CONVERT command is used to change the format of a host number from
Internet  to  decimal or octal, from decimal to Internet or octal, and
from octal to decimal or Internet.   The  CONVERT  command  takes  the
form:

     IPHOST>CONVERT (A HOST NUMBER FROM)decimal,internet, octal <RET>

where decimal, internet, and octal followed by a  number  specify  the
address of the host you want information about.

The following examples show the three formats of the CONVERT command:

     IPHOST>CONVERT (A HOST NUMBER FROM)INTERNET 010.001.000.079<RET>
      Internet: 010.001.000.079, Decimal: 167837775, Octal: 1200200117


     IPHOST>CONVERT (A HOST NUMBER FROM) DECIMAL 167837775 <RET>
      Internet: 010.001.000.079, Decimal: 167837775, Octal: 1200200117


     IPHOST>CONVERT (A HOST NUMBER FROM) OCTAL 1200200117 <RET>
      Internet: 010.001.000.079, Decimal: 167837775, Octal: 1200200117


ARPANET COMMAND

The ARPANET command is a privileged command that is used to cycle  the
ARPANET  up and down.  Any one of three words is used to complete this
command:  initialize, status, and state.  The  ARPANET  command  takes
the form:

     IPHOST>ARPANET command word <RET>

where command word is either initialize, status, or state.

The ARPANET INITIALIZE command is  used  to  reload  host  or  gateway
tables.  This command takes the form:

     IPHOST>ARPANET INITIALIZE HOST (TABLES)<RET>

          or

     IPHOST>ARPANET INITIALIZE GATEWAY (TABLES)<RET>
IPHOST                                                        Page 5-5


where a carriage return confirms the command.

The ARPANET STATUS command tells you whether  the  ARPANET  is  up  or
down.  This command takes the form:

     IPHOST>ARPANET STATUS <RET>

where a carriage return confirms the command.  Following the execution
of  this  command,  an  informational  message  is  displayed  at your
terminal:

     Network interface is down
     Network interface output is disabled
     Network service is enabled
     Last network interface off tansition: 18-Nov-83 14:16:17

The ARPANET STATE command is used  to  bring  up  or  bring  down  the
ARPANET.  This command takes the form:

     IPHOST>ARPANET STATE (IS) ON OFF<RET>

where the arguments ON or OFF are used to complete the  command.   The
ON  argument turns the ARPANET on.  The OFF argument turns the ARPANET
off.  An example of the ARPANET STATE command  with  the  argument  ON
follows:

     IPHOST>ARPANET STATE (IS) ON <RET>



5.6  IPHOST MESSAGES

The most common IPHOST messages,  their  descriptions,  and  suggested
user responses are listed alphabetically below.  When IPHOST is unable
to continue with a user command, it outputs one of the error  messages
listed  below.   The errors are generally errors in the user's command
line.  Fatal errors are preceded by a question mark (?),  and  warning
messages are preceded by a percent sign (%).

%Does not match switch or keyword

     You specified a keyword or switch that is not valid.

     SUGGESTED USER RESPONSE: Correct the keyword or switch and try 
     the command again. 

%Name for Host not found

     You specified an invalid host name. 

     SUGGESTED USER RESPONSE: Check to see that you have specified a 
     valid host name. Check the spelling of the host name to make 
     sure that you have typed it correctly.

%Special Privileges are required for this command.
IPHOST                                                        Page 5-6


     You have tried to execute an ARPANET command without 
     WHEEL or OPERATOR privileges enabled.

     SUGGESTED USER RESPONSE:  Enable WHEEL or OPERATOR privileges 
     before executing this command.