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

NAME
     ftpd - Internet File Transfer Protocol server

SYNOPSIS
     ftpd [-46ADEORSUdro] [-l [-l]] [-T maxtimeout] [-a address] [-p file]
          [-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:

     -4      When -D is specified, accept IPv4 connections.  When -6 is also
             specified, accept IPv4 connection via AF_INET6 socket.  When -6
             is not specified, accept IPv4 connection via AF_INET socket.

     -6      When -D is specified, accept connections via AF_INET6 socket.

     -A      Allow only anonymous ftp access.

     -D      With this option set, ftpd will detach and become a daemon,
             accepting connections on the FTP port and forking children
             processes to handle them.  This is lower overhead than starting
             ftpd from inetd(8) and is thus useful on busy servers to reduce
             load.

     -E      Disable the EPSV command.  This is useful for servers behind
             older firewalls.

     -O      Put server in write-only mode for anonymous users only.  RETR is
             disabled for anonymous users, preventing anonymous downloads.
             This has no effect if -o is also specified.

     -R      With this option set, ftpd will revert to historical behavior
             with regard to security checks on user operations and
             restrictions on PORT requests.  Currently, ftpd will only honor
             PORT commands directed to unprivileged ports on the remote user's
             host (which violates the FTP protocol specification but closes
             some security holes).

     -S      With this option set, ftpd logs all anonymous file downloads to
             the file /var/log/ftpd when this file exists.

     -U      In previous versions of ftpd, when a passive mode client
             requested a data connection to the server, the server would use
             data ports in the range 1024..4999.  Now, by default, the server
             will use data ports in the range 49152..65535.  Specifying this
             option will revert to the old behavior.

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

     -r      Put server in read-only mode.  All commands which may modify the
             local filesystem are disabled.

     -o      Put server in write-only mode.  RETR is disabled, preventing
             downloads.

     -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
             arguments are also logged.  Note: LOG_FTP messages are not
             displayed by syslogd(8) by default, and may have to be enabled in
             syslogd(8)'s configuration file.

     -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.

     -a      When -D is specified, accept connections only on the specified
             address.

     -p      When -D is specified, write the daemon's process ID to file.

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

     The file /var/run/nologin can be used to disable ftp access.  If the file
     exists, ftpd displays it and exits.  If the file /etc/ftpwelcome exists,
     ftpd prints it before issuing the ``ready'' message.  If the file
     /etc/ftpmotd exists, ftpd prints it after a successful login.  Note the
     motd file used is the one relative to the login environment.  This means
     the one in ~ftp/etc in the anonymous user's case.

     The ftp server currently supports the following ftp requests.  The case
     of the requests is ignored.  Requests marked [RW] are disabled if -r is
     specified.

           Request    Description
           ABOR       abort previous command
           ACCT       specify account (ignored)
           ALLO       allocate storage (vacuously)
           APPE       append to a file [RW]
           CDUP       change to parent of current working directory
           CWD        change working directory
           DELE       delete a file [RW]
           EPRT       specify data connection port, multiprotocol
           EPSV       prepare for server-to-server transfer, multiprotocol
           HELP       give help information
           LIST       give list files in a directory (``ls -lgA'')
           LPRT       specify data connection port, multiprotocol
           LPSV       prepare for server-to-server transfer, multiprotocol
           MDTM       show last modification time of file
           MKD        make a directory [RW]
           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 [RW]
           RNFR       specify rename-from file name [RW]
           RNTO       specify rename-to file name [RW]
           SITE       non-standard commands (see next section)
           SIZE       return size of file
           STAT       return status of server
           STOR       store a file [RW]
           STOU       store a file with a unique name [RW]
           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) [RW]
           XPWD       print the current working directory (deprecated)
           XRMD       remove a directory (deprecated) [RW]

     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 [RW], e.g. ``SITE CHMOD 755
                      filename''
           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
     command 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 six rules.

           1.   The login name must be in the password data base and not have
                a null password.  In this case a password must be provided by
                the client before any file operations may be performed.  If
                the user has an S/Key key, the response from a successful USER
                command will include an S/Key challenge.  The client may
                choose to respond with a PASS command giving either a standard
                password or an S/Key one-time password.  The server will
                automatically determine which type of password it has been
                given and attempt to authenticate accordingly.  See key(1) for
                more information on S/Key authentication.  S/Key is a
                Trademark of Bellcore.

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

           3.   The login name must not be a member of a group specified in
                the file /etc/ftpusers.  Entries in this file interpreted as
                group names are prefixed by an "at" `@' sign.

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

           5.   If the user name appears in the file /etc/ftpchroot, or the
                user is a member of a group with a group entry in this file,
                i.e. one prefixed with `@', the session's root will be changed
                to the user's login directory by chroot(2) as for an
                ``anonymous'' or ``ftp'' account (see next item).  This
                facility may also be triggered by enabling the boolean "ftp-
                chroot" capability in login.conf(5).  However, the user must
                still supply a password.  This feature is intended as a
                compromise between a fully anonymous account and a fully
                privileged account.  The account should also be set up as for
                an anonymous account.

           6.   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).  When the -S option is set, all
                transfers are logged as well.

     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,
     following these rules:

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

           ~ftp/etc  Make this directory owned by ``root'' and unwritable by
                     anyone (mode 555).  The files pwd.db (see 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 ftpmotd, if present, will be printed
                     after a successful login.  These files should be mode
                     444.

           ~ftp/pub  This directory and the subdirectories beneath it should
                     be owned by the users and groups responsible for placing
                     files in them, and be writable only by them (mode 755 or
                     775).  They should not be owned or writable by ``ftp'' or
                     its group, otherwise guest users can fill the drive with
                     unwanted files.

     If the system has multiple IP addresses, ftpd supports the idea of
     virtual hosts, which provides the ability to define multiple anonymous
     ftp areas, each one allocated to a different internet address.  The file
     /etc/ftphosts contains information pertaining to each of the virtual
     hosts.  Each host is defined on its own line which contains a number of
     fields separated by whitespace:

           hostname  Contains the hostname or IP address of the virtual host.

           user      Contains a user record in the system password file.  As
                     with normal anonymous ftp, this user's access uid, gid
                     and group memberships determine file access to the
                     anonymous ftp area.  The anonymous ftp area (to which any
                     user is chrooted on login) is determined by the home
                     directory defined for the account.  User id and group for
                     any ftp account may be the same as for the standard ftp
                     user.

           statfile  File to which all file transfers are logged, which
                     defaults to /var/log/ftpd.

           welcome   This file is the welcome message displayed before the
                     server ready prompt.  It defaults to /etc/ftpwelcome.

           motd      This file is displayed after the user logs in.  It
                     defaults to /etc/ftpmotd.

     Lines beginning with a '#' are ignored and can be used to include
     comments.

     Defining a virtual host for the primary IP address or hostname changes
     the default for ftp logins to that address.  The 'user', 'statfile',
     'welcome' and 'motd' fields may be left blank, or a single hypen '-' used
     to indicate that the default value is to be used.

     As with any anonymous login configuration, due care must be given to
     setup and maintenance to guard against security related problems.

     ftpd has internal support for handling remote requests to list files, and
     will not execute /bin/ls in either a chrooted or non-chrooted
     environment.  The ~/bin/ls executable need not be placed into the
     chrooted tree, nor need the ~/bin directory exist.

FILES
     /etc/ftpusers    List of unwelcome/restricted users.
     /etc/ftpchroot   List of normal users who should be chroot'd.
     /etc/ftphosts    Virtual hosting configuration file.
     /etc/ftpwelcome  Welcome notice.
     /etc/ftpmotd     Welcome notice after login.
     /var/run/nologin
                      Displayed and access refused.
     /var/log/ftpd    Log file for anonymous transfers.

SEE ALSO
     ftp(1), key(1), getusershell(3), login.conf(5), inetd(8), 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
     possibly incomplete.

HISTORY
     The ftpd command appeared in 4.2BSD.  IPv6 support was added in WIDE
     Hydrangea IPv6 stack kit.

FreeBSD 11.0-PRERELEASE        January 27, 2000        FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | BUGS | HISTORY

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