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FTPD(8)                   BSD System Manager's Manual                  FTPD(8)

NAME
     ftpd - Internet File Transfer Protocol server

SYNOPSIS
     ftpd [-dl] [-T maxtimeout] [-t timeout]

DESCRIPTION
     Ftpd is the Internet File Transfer Protocol server process.  The server
     uses the TCP protocol and listens at the port specified in the ``ftp''
     service specification; see services(5).

     Available options:

     -d      Debugging information is written to the syslog using LOG_FTP.

     -l      Each successful and failed ftp(1) session is logged using syslog
             with a facility of LOG_FTP.  If this option is specified twice,
             the retrieve (get), store (put), append, delete, make directory,
             remove directory and rename operations and their filename argu-
             ments are also logged.

     -T      A client may also request a different timeout period; the maximum
             period allowed may be set to timeout seconds with the -T option.
             The default limit is 2 hours.

     -t      The inactivity timeout period is set to timeout seconds (the de-
             fault is 15 minutes).

     The file /etc/nologin can be used to disable ftp access.  If the file ex-
     ists, ftpd displays it and exits.  If the file /etc/ftpwelcome exists,
     ftpd prints it before issuing the ``ready'' message.  If the file
     /etc/motd exists, ftpd prints it after a successful login.

     The ftp server currently supports the following ftp requests.  The case
     of the requests is ignored.

           Request    Description
           ABOR       abort previous command
           ACCT       specify account (ignored)
           ALLO       allocate storage (vacuously)
           APPE       append to a file
           CDUP       change to parent of current working directory
           CWD        change working directory
           DELE       delete a file
           HELP       give help information
           LIST       give list files in a directory (``ls -lgA'')
           MKD        make a directory
           MDTM       show last modification time of file
           MODE       specify data transfer mode
           NLST       give name list of files in directory
           NOOP       do nothing
           PASS       specify password
           PASV       prepare for server-to-server transfer
           PORT       specify data connection port
           PWD        print the current working directory
           QUIT       terminate session
           REST       restart incomplete transfer
           RETR       retrieve a file
           RMD        remove a directory
           RNFR       specify rename-from file name
           RNTO       specify rename-to file name


           SITE       non-standard commands (see next section)
           SIZE       return size of file
           STAT       return status of server
           STOR       store a file
           STOU       store a file with a unique name
           STRU       specify data transfer structure
           SYST       show operating system type of server system
           TYPE       specify data transfer type
           USER       specify user name
           XCUP       change to parent of current working directory
                      (deprecated)
           XCWD       change working directory (deprecated)
           XMKD       make a directory (deprecated)
           XPWD       print the current working directory (deprecated)
           XRMD       remove a directory (deprecated)

     The following non-standard or UNIX specific commands are supported by the
     SITE request.

           Request    Description
           UMASK      change umask, e.g. ``SITE UMASK 002''
           IDLE       set idle-timer, e.g. ``SITE IDLE 60''
           CHMOD      change mode of a file, e.g. ``SITE CHMOD0 0CHMOD1
                      1CHMOD2
           HELP       give help information.

     The remaining ftp requests specified in Internet RFC 959 are recognized,
     but not implemented.  MDTM and SIZE are not specified in RFC 959, but
     will appear in the next updated FTP RFC.

     The ftp server will abort an active file transfer only when the ABOR com-
     mand is preceded by a Telnet "Interrupt Process" (IP) signal and a Telnet
     "Synch" signal in the command Telnet stream, as described in Internet RFC
     959.  If a STAT command is received during a data transfer, preceded by a
     Telnet IP and Synch, transfer status will be returned.

     Ftpd interprets file names according to the ``globbing'' conventions used
     by csh(1).  This allows users to utilize the metacharacters ``*?[]{}~''.

     Ftpd authenticates users according to three rules.

           1.   The login name must be in the password data base, /etc/passwd,
                and not have a null password.  In this case a password must be
                provided by the client before any file operations may be per-
                formed.

           2.   The login name must not appear in the file /etc/ftpusers.

           3.   The user must have a standard shell returned by
                getusershell(3).

           4.   If the user name is ``anonymous'' or ``ftp'', an anonymous ftp
                account must be present in the password file (user ``ftp'').
                In this case the user is allowed to log in by specifying any
                password (by convention an email address for the user should
                be used as the password).

     In the last case, ftpd takes special measures to restrict the client's
     access privileges.  The server performs a chroot(2) to the home directory
     of the ``ftp'' user.  In order that system security is not breached, it
     is recommended that the ``ftp'' subtree be constructed with care, follow-
     ing these rules:

           ~ftp      Make the home directory owned by ``root'' and unwritable



                     by anyone.

           ~ftp/bin  Make this directory owned by ``root'' and unwritable by
                     anyone (mode 555).  The program ls(1) must be present to
                     support the list command.  This program should be mode
                     111.

           ~ftp/etc  Make this directory owned by ``root'' and unwritable by
                     anyone (mode 555).  The files passwd(5) and group(5) must
                     be present for the ls command to be able to produce owner
                     names rather than numbers.  The password field in passwd
                     is not used, and should not contain real passwords.  The
                     file motd, if present, will be printed after a successful
                     login.  These files should be mode 444.

           ~ftp/pub  Make this directory mode 777 and owned by ``ftp''. Guests
                     can then place files which are to be accessible via the
                     anonymous account in this directory.

FILES
     /etc/ftpusers    List of unwelcome/restricted users.
     /etc/ftpwelcome  Welcome notice.
     /etc/motd        Welcome notice after login.
     /etc/nologin     Displayed and access refused.

SEE ALSO
     ftp(1),  getusershell(3),  syslogd(8)

BUGS
     The server must run as the super-user to create sockets with privileged
     port numbers.  It maintains an effective user id of the logged in user,
     reverting to the super-user only when binding addresses to sockets.  The
     possible security holes have been extensively scrutinized, but are possi-
     bly incomplete.

HISTORY
     The ftpd command appeared in 4.2BSD.

4.2 Berkeley Distribution        June 1, 1994                                3