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32 .\" @(#)ftpd.8 8.2 (Berkeley) 4/19/94
40 .Nd Internet File Transfer Protocol server
43 .Op Fl 468ADdEhMmOoRrSUvW
48 .Op Fl T Ar maxtimeout
55 Internet File Transfer Protocol
60 and listens at the port specified with the
64 service specification; see
68 .Bl -tag -width indent
72 is specified, accept connections via
78 is specified, accept connections via
82 Enable transparent UTF-8 mode.
83 RFC\ 2640 compliant clients will be told that the character encoding
84 used by the server is UTF-8, which is the only effect of the option.
86 This option does not enable any encoding conversion for server file names;
87 it implies instead that the names of files on the server are encoded
89 As for files uploaded via FTP, it is the duty of the RFC\ 2640 compliant
90 client to convert their names from the client's local encoding to UTF-8.
91 FTP command names and own
93 messages are always encoded in ASCII, which is a subset of UTF-8.
94 Hence no need for server-side conversion at all.
96 Allow only anonymous ftp access.
100 is specified, accept connections only on the specified
103 With this option set,
105 will detach and become a daemon, accepting connections on the FTP port and
106 forking children processes to handle them.
107 This is lower overhead than starting
111 and is thus useful on busy servers to reduce load.
113 Debugging information is written to the syslog using
116 Disable the EPSV command.
117 This is useful for servers behind older firewalls.
119 Disable printing host-specific information, such as the
120 server software version or hostname, in server messages.
122 Each successful and failed
124 session is logged using syslog with a facility of
126 If this option is specified twice, the retrieve (get), store (put), append,
127 delete, make directory, remove directory and rename operations and
128 their filename arguments are also logged.
132 .Pa /var/log/xferlog .
134 Prevent anonymous users from creating directories.
136 Permit anonymous users to overwrite or modify
137 existing files if allowed by file system permissions.
138 By default, anonymous users cannot modify existing files;
139 in particular, files to upload will be created under a unique name.
141 Put server in write-only mode for anonymous users only.
142 RETR is disabled for anonymous users, preventing anonymous downloads.
143 This has no effect if
147 Put server in write-only mode.
148 RETR is disabled, preventing downloads.
152 is specified, accept connections at
154 specified as a numeric value or service name, instead of at the default
160 is specified, write the daemon's process ID to
162 instead of the default pid file,
163 .Pa /var/run/ftpd.pid .
165 With this option set,
167 will revert to historical behavior with regard to security checks on
168 user operations and restrictions on PORT requests.
171 will only honor PORT commands directed to unprivileged ports on the
172 remote user's host (which violates the FTP protocol specification but
173 closes some security holes).
175 Put server in read-only mode.
176 All commands which may modify the local file system are disabled.
178 With this option set,
180 logs all anonymous file downloads to the file
182 when this file exists.
184 A client may also request a different timeout period;
185 the maximum period allowed may be set to
190 The default limit is 2 hours.
192 The inactivity timeout period is set to
194 seconds (the default is 15 minutes).
196 This option instructs ftpd to use data ports in the range of
197 .Dv IP_PORTRANGE_DEFAULT
198 instead of in the range of
199 .Dv IP_PORTRANGE_HIGH .
200 Such a change may be useful for some specific firewall configurations;
203 for more information.
205 Note that option is a virtual no-op in
208 ranges are identical by default.
210 The default file creation mode mask is set to
212 which is expected to be an octal numeric value.
216 This option may be overridden by
222 Do not log FTP sessions to the user accounting database.
227 can be used to disable ftp access.
230 displays it and exits.
235 prints it before issuing the
242 prints it after a successful login.
243 Note the motd file used is the one
244 relative to the login environment.
245 This means the one in
247 in the anonymous user's case.
249 The ftp server currently supports the following ftp requests.
250 The case of the requests is ignored.
251 Requests marked [RW] are
255 .Bl -column "Request" -offset indent
256 .It Sy Request Ta Sy "Description"
257 .It ABOR Ta "abort previous command"
258 .It ACCT Ta "specify account (ignored)"
259 .It ALLO Ta "allocate storage (vacuously)"
260 .It APPE Ta "append to a file [RW]"
261 .It CDUP Ta "change to parent of current working directory"
262 .It CWD Ta "change working directory"
263 .It DELE Ta "delete a file [RW]"
264 .It EPRT Ta "specify data connection port, multiprotocol"
265 .It EPSV Ta "prepare for server-to-server transfer, multiprotocol"
266 .It FEAT Ta "give information on extended features of server"
267 .It HELP Ta "give help information"
268 .It LIST Ta "give list files in a directory" Pq Dq Li "ls -lgA"
269 .It LPRT Ta "specify data connection port, multiprotocol"
270 .It LPSV Ta "prepare for server-to-server transfer, multiprotocol"
271 .It MDTM Ta "show last modification time of file"
272 .It MKD Ta "make a directory [RW]"
273 .It MODE Ta "specify data transfer" Em mode
274 .It NLST Ta "give name list of files in directory"
275 .It NOOP Ta "do nothing"
276 .It PASS Ta "specify password"
277 .It PASV Ta "prepare for server-to-server transfer"
278 .It PORT Ta "specify data connection port"
279 .It PWD Ta "print the current working directory"
280 .It QUIT Ta "terminate session"
281 .It REST Ta "restart incomplete transfer"
282 .It RETR Ta "retrieve a file"
283 .It RMD Ta "remove a directory [RW]"
284 .It RNFR Ta "specify rename-from file name [RW]"
285 .It RNTO Ta "specify rename-to file name [RW]"
286 .It SITE Ta "non-standard commands (see next section)"
287 .It SIZE Ta "return size of file"
288 .It STAT Ta "return status of server"
289 .It STOR Ta "store a file [RW]"
290 .It STOU Ta "store a file with a unique name [RW]"
291 .It STRU Ta "specify data transfer" Em structure
292 .It SYST Ta "show operating system type of server system"
293 .It TYPE Ta "specify data transfer" Em type
294 .It USER Ta "specify user name"
295 .It XCUP Ta "change to parent of current working directory (deprecated)"
296 .It XCWD Ta "change working directory (deprecated)"
297 .It XMKD Ta "make a directory (deprecated) [RW]"
298 .It XPWD Ta "print the current working directory (deprecated)"
299 .It XRMD Ta "remove a directory (deprecated) [RW]"
302 The following non-standard or
304 specific commands are supported
308 .Bl -column Request -offset indent
309 .It Sy Request Ta Sy Description
310 .It UMASK Ta change umask, e.g. ``SITE UMASK 002''
311 .It IDLE Ta set idle-timer, e.g. ``SITE IDLE 60''
312 .It CHMOD Ta "change mode of a file [RW], e.g. ``SITE CHMOD 755 filename''"
313 .It MD5 Ta "report the files MD5 checksum, e.g. ``SITE MD5 filename''"
314 .It HELP Ta give help information
317 Note: SITE requests are disabled in case of anonymous logins.
319 The remaining ftp requests specified in Internet RFC 959
321 recognized, but not implemented.
322 MDTM and SIZE are not specified in RFC 959, but will appear in the
323 next updated FTP RFC.
324 To avoid possible denial-of-service attacks, SIZE requests against
325 files larger than 10240 bytes will be denied if the current transfer
328 The ftp server will abort an active file transfer only when the
330 command is preceded by a Telnet "Interrupt Process" (IP)
331 signal and a Telnet "Synch" signal in the command Telnet stream,
332 as described in Internet RFC 959.
335 command is received during a data transfer, preceded by a Telnet IP
336 and Synch, transfer status will be returned.
340 utility interprets file names according to the
344 This allows users to utilize the metacharacters
349 utility authenticates users according to six rules.
351 .Bl -enum -offset indent
353 The login name must be in the password data base
354 and not have a null password.
355 In this case a password must be provided by the client before any
356 file operations may be performed.
357 If the user has an OPIE key, the response from a successful USER
358 command will include an OPIE challenge.
359 The client may choose to respond with a PASS command giving either
360 a standard password or an OPIE one-time password.
361 The server will automatically determine which type of
362 password it has been given and attempt to authenticate accordingly.
365 for more information on OPIE authentication.
367 The login name must not appear in the file
370 The login name must not be a member of a group specified in the file
372 Entries in this file interpreted as group names are prefixed by an "at"
376 The user must have a standard shell returned by
379 If the user name appears in the file
381 or the user is a member of a group with a group entry in this file,
382 i.e., one prefixed with
384 the session's root will be changed to the directory specified
385 in this file or to the user's login directory by
391 account (see next item).
394 for a detailed description of the format of this file.
395 This facility may also be triggered by enabling the boolean "ftp-chroot"
398 However, the user must still supply a password.
399 This feature is intended as a compromise between a fully anonymous
400 account and a fully privileged account.
401 The account should also be set up as for an anonymous account.
408 anonymous ftp account must be present in the password
411 In this case the user is allowed
412 to log in by specifying any password (by convention an email address for
413 the user should be used as the password).
416 option is set, all transfers are logged as well.
421 takes special measures to restrict the client's access privileges.
422 The server performs a
424 to the home directory of the
427 As a special case if the
429 user's home directory pathname contains the
433 uses its left-hand side as the name of the directory to do
435 to, and its right-hand side to change the current directory to afterwards.
436 A typical example for this case would be
437 .Pa /usr/local/ftp/./pub .
438 In order that system security is not breached, it is recommended
441 subtree be constructed with care, following these rules:
442 .Bl -tag -width "~ftp/pub" -offset indent
444 Make the home directory owned by
446 and unwritable by anyone.
448 Make this directory owned by
450 and unwritable by anyone (mode 555).
451 The files pwd.db (see
455 must be present for the
457 command to be able to produce owner names rather than numbers.
458 The password field in
460 is not used, and should not contain real passwords.
463 if present, will be printed after a successful login.
464 These files should be mode 444.
466 This directory and the subdirectories beneath it should be owned
467 by the users and groups responsible for placing files in them,
468 and be writable only by them (mode 755 or 775).
471 be owned or writable by
473 or its group, otherwise guest users
474 can fill the drive with unwanted files.
477 If the system has multiple IP addresses,
479 supports the idea of virtual hosts, which provides the ability to
480 define multiple anonymous ftp areas, each one allocated to a different
484 contains information pertaining to each of the virtual hosts.
485 Each host is defined on its own line which contains a number of
486 fields separated by whitespace:
487 .Bl -tag -offset indent -width hostname
489 Contains the hostname or IP address of the virtual host.
491 Contains a user record in the system password file.
492 As with normal anonymous ftp, this user's access uid, gid and group
493 memberships determine file access to the anonymous ftp area.
494 The anonymous ftp area (to which any user is chrooted on login)
495 is determined by the home directory defined for the account.
496 User id and group for any ftp account may be the same as for the
499 File to which all file transfers are logged, which
503 This file is the welcome message displayed before the server ready
506 .Pa /etc/ftpwelcome .
508 This file is displayed after the user logs in.
513 Lines beginning with a '#' are ignored and can be used to include
516 Defining a virtual host for the primary IP address or hostname
517 changes the default for ftp logins to that address.
518 The 'user', 'statfile', 'welcome' and 'motd' fields may be left
519 blank, or a single hyphen '-' used to indicate that the default
522 As with any anonymous login configuration, due care must be given
523 to setup and maintenance to guard against security related problems.
527 utility has internal support for handling remote requests to list
528 files, and will not execute
530 in either a chrooted or non-chrooted environment.
533 executable need not be placed into the chrooted tree, nor need the
537 .Bl -tag -width ".Pa /var/run/ftpd.pid" -compact
539 List of unwelcome/restricted users.
540 .It Pa /etc/ftpchroot
541 List of normal users who should be chroot'd.
543 Virtual hosting configuration file.
544 .It Pa /etc/ftpwelcome
547 Welcome notice after login.
548 .It Pa /var/run/ftpd.pid
549 Default pid file for daemon mode.
550 .It Pa /var/run/nologin
551 Displayed and access refused.
553 Log file for anonymous transfers.
554 .It Pa /var/log/xferlog
555 Default place for session logs.
571 IPv6 support was added in WIDE Hydrangea IPv6 stack kit.
573 The server must run as the super-user
574 to create sockets with privileged port numbers.
576 an effective user id of the logged in user, reverting to
577 the super-user only when binding addresses to sockets.
579 possible security holes have been extensively
580 scrutinized, but are possibly incomplete.