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

     ftpd -- Internet File Transfer Protocol server

     ftpd [-46ADdEhMmOoRrSUvW] [-l [-l]] [-a address] [-P port]	[-p file]
	  [-T maxtimeout] [-t timeout] [-u umask]

     The ftpd utility is the Internet File Transfer Protocol server process.
     The server	uses the TCP protocol and listens at the port specified	with
     the -P option or in the "ftp" service specification; see services(5).

     Available options:

     -4	     When -D is	specified, accept connections via AF_INET socket.

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

     -A	     Allow only	anonymous ftp access.

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

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

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

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

     -h	     Disable printing host-specific information, such as the server
	     software version or hostname, in server messages.

     -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.  By	default, syslogd(8) logs these to

     -M	     Prevent anonymous users from creating directories.

     -m	     Permit anonymous users to overwrite or modify existing files if
	     allowed by	file system permissions.  By default, anonymous	users
	     cannot modify existing files; in particular, files	to upload will
	     be	created	under a	unique name.

     -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.

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

     -P	     When -D is	specified, accept connections at port, specified as a
	     numeric value or service name, instead of at the default "ftp"

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

     -R	     With this option set, ftpd	will revert to historical behavior
	     with regard to security checks on user operations and restric-
	     tions 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).

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

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

     -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).

     -U	     This option instructs ftpd	to use data ports in the range of
	     IP_PORTRANGE_DEFAULT instead of in	the range of
	     IP_PORTRANGE_HIGH.	 Such a	change may be useful for some specific
	     firewall configurations; see ip(4)	for more information.

	     Note that option is a virtual no-op in FreeBSD 5.0	and above;
	     both port ranges are indentical by	default.

     -u	     The default file creation mode mask is set	to umask, which	is ex-
	     pected to be an octal numeric value.  Refer to umask(2) for de-
	     tails.  This option may be	overridden by login.conf(5).

     -v	     A synonym for -d.

     -W	     Do	not log	FTP sessions to	/var/log/wtmp.

     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

	   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
	   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
	   MD5	      report the files MD5 checksum, e.g. ``SITE MD5
	   HELP	      give help	information

     Note: SITE	requests are disabled in case of anonymous logins.

     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.  To avoid	possible denial-of-
     service attacks, SIZE requests against files larger than 10240 bytes will
     be	denied if the current transfer type is ASCII.

     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.

     The ftpd utility interprets file names according to the "globbing"	con-
     ventions used by csh(1).  This allows users to utilize the	metacharacters

     The ftpd utility 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 auto-
		matically 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

	   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

	   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 directory specified in this file	or to the
		user's login directory by chroot(2) as for an "anonymous" or
		"ftp" account (see next	item).	See ftpchroot(5) for a de-
		tailed description of the format of this file.	This facility
		may also be triggered by enabling the boolean "ftp-chroot" ca-
		pability in login.conf(5).  However, the user must still sup-
		ply a password.	 This feature is intended as a compromise be-
		tween a	fully anonymous	account	and a fully privileged ac-
		count.	The account should also	be set up as for an anonymous

	   6.	If the user name is "anonymous"	or "ftp", an anonymous ftp ac-
		count 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.	 As a special case if the "ftp"	user's home directory
     pathname contains the /./ separator, ftpd uses its	left-hand side as the
     name of the directory to do chroot(2) to, and its right-hand side to
     change the	current	directory to afterwards.  A typical example for	this
     case would	be /usr/local/ftp/./pub.  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

	   ~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(1) command to be able
		     to	produce	owner names rather than	numbers.  The password
		     field in passwd(5)	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	vir-
     tual 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	anony-
		     mous 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	de-
		     faults 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	de-
		     faults to /etc/ftpmotd.

     Lines beginning with a '#'	are ignored and	can be used to include com-

     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	hyphen '-'
     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.

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

     /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.
     /var/log/xferlog  Default place for session logs.

     ftp(1), key(1), umask(2), getusershell(3),	ftpchroot(5), login.conf(5),
     inetd(8), syslogd(8)

     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.

     The ftpd utility appeared in 4.2BSD.  IPv6	support	was added in WIDE Hy-
     drangea IPv6 stack	kit.

BSD			       January 27, 2000				   BSD


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