    Network Working Group                                      Jim Lieb
    RFC # 697                                                  SUMEX-AIM
    NIC # 32963                                                July 14, 1975

                               CWD Command of FTP

    Introduction

    The Tenex file system support a "files only" directory.  This type of
    directory cannot be "logged in" but it can be "connected to".  A login
    gives directory "owner" access to the job generated by the system and an
    address space in which the user can execute programs.   A connect allows
    an existing job and its associated user "owner" access to a directory
    but creates no address space.  The words "owner", "group", and
    "universal" or "public" determine which field of the protection
    specification is to be used to check the legality of a file access
    request.

    Problem

    The Tenex FTP server does not allow an FTP Login to a "files only"
    directory.  The current protocol contains the CWD (Change Working
    Directory) command which gets part of the "connect" functions but it
    does not grant "owner" access to the user.  Therefore, there is no way a
    user can access a "files only" directory as the "owner" (i.e. he can
    supply the password).  This is undesirable for private directories of
    this type since it is uneconomical to define a user - directory "group"
    for so few directories and unrestricted "public" access may be
    undesirable.

    Solution

    There are two approach we can take.  Either we remove the distinction
    "files only" from the FTP login, or we create a command that does the
    "connect" function.  The restriction placed on "files only" directories
    is based on how we define a user of FTP to the server.  If we say that
    any net user who knows the password to a directory has ownership of that
    directory as far as FTP is concerned, then we have a solution.  If we
    want an FTP login to be as restrictive as a user login, then we need the
    second alternative.

    Lieb                                                            [Page 1]

    RFC 697                    CWD Command of FTP                  July 1975

    Proposal

    Change the protocol in one of the following ways:

    1.  Remove the restriction on "files only" directories for FTP logins or

    2.  Add an optional argument to the CWD (Change Working Directory)
        command to specify the password string for the directory.  If the
        password check is successful the user is granted ownership rights to
        that directory.  If the password is not present or the check fails,
        the command functions as it presently does and access is controlled
        by the current protection mechanism.  Anonymous users should not be
        allowed to use this mechanism to change their access to the file
        system.

           [ This RFC was put into machine readable form for entry ]
           [ into the online RFC archives by Alex McKenzie with    ]
           [ support from GTE, formerly BBN Corp.            10/99 ]

    Lieb                                                            [Page 2]