1.\" Copyright (c) 1985, 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)ftpd.8 8.2 (Berkeley) 4/19/94 33.\" $FreeBSD$ 34.\" 35.Dd January 21, 2010 36.Dt FTPD 8 37.Os 38.Sh NAME 39.Nm ftpd 40.Nd Internet File Transfer Protocol server 41.Sh SYNOPSIS 42.Nm 43.Op Fl 468ADdEhMmOoRrSUvW 44.Op Fl l Op Fl l 45.Op Fl a Ar address 46.Op Fl P Ar port 47.Op Fl p Ar file 48.Op Fl T Ar maxtimeout 49.Op Fl t Ar timeout 50.Op Fl u Ar umask 51.Sh DESCRIPTION 52The 53.Nm 54utility is the 55Internet File Transfer Protocol 56server process. 57The server uses the 58.Tn TCP 59protocol 60and listens at the port specified with the 61.Fl P 62option or in the 63.Dq ftp 64service specification; see 65.Xr services 5 . 66.Pp 67Available options: 68.Bl -tag -width indent 69.It Fl 4 70When 71.Fl D 72is specified, accept connections via 73.Dv AF_INET 74socket. 75.It Fl 6 76When 77.Fl D 78is specified, accept connections via 79.Dv AF_INET6 80socket. 81.It Fl 8 82Enable transparent UTF-8 mode. 83RFC\ 2640 compliant clients will be told that the character encoding 84used by the server is UTF-8, which is the only effect of the option. 85.Pp 86This option does not enable any encoding conversion for server file names; 87it implies instead that the names of files on the server are encoded 88in UTF-8. 89As for files uploaded via FTP, it is the duty of the RFC\ 2640 compliant 90client to convert their names from the client's local encoding to UTF-8. 91FTP command names and own 92.Nm 93messages are always encoded in ASCII, which is a subset of UTF-8. 94Hence no need for server-side conversion at all. 95.It Fl A 96Allow only anonymous ftp access. 97.It Fl a 98When 99.Fl D 100is specified, accept connections only on the specified 101.Ar address . 102.It Fl D 103With this option set, 104.Nm 105will detach and become a daemon, accepting connections on the FTP port and 106forking children processes to handle them. 107This is lower overhead than starting 108.Nm 109from 110.Xr inetd 8 111and is thus useful on busy servers to reduce load. 112.It Fl d 113Debugging information is written to the syslog using 114.Dv LOG_FTP . 115.It Fl E 116Disable the EPSV command. 117This is useful for servers behind older firewalls. 118.It Fl h 119Disable printing host-specific information, such as the 120server software version or hostname, in server messages. 121.It Fl l 122Each successful and failed 123.Xr ftp 1 124session is logged using syslog with a facility of 125.Dv LOG_FTP . 126If this option is specified twice, the retrieve (get), store (put), append, 127delete, make directory, remove directory and rename operations and 128their filename arguments are also logged. 129By default, 130.Xr syslogd 8 131logs these to 132.Pa /var/log/xferlog . 133.It Fl M 134Prevent anonymous users from creating directories. 135.It Fl m 136Permit anonymous users to overwrite or modify 137existing files if allowed by file system permissions. 138By default, anonymous users cannot modify existing files; 139in particular, files to upload will be created under a unique name. 140.It Fl O 141Put server in write-only mode for anonymous users only. 142RETR is disabled for anonymous users, preventing anonymous downloads. 143This has no effect if 144.Fl o 145is also specified. 146.It Fl o 147Put server in write-only mode. 148RETR is disabled, preventing downloads. 149.It Fl P 150When 151.Fl D 152is specified, accept connections at 153.Ar port , 154specified as a numeric value or service name, instead of at the default 155.Dq ftp 156port. 157.It Fl p 158When 159.Fl D 160is specified, write the daemon's process ID to 161.Ar file 162instead of the default pid file, 163.Pa /var/run/ftpd.pid . 164.It Fl R 165With this option set, 166.Nm 167will revert to historical behavior with regard to security checks on 168user operations and restrictions on PORT requests. 169Currently, 170.Nm 171will only honor PORT commands directed to unprivileged ports on the 172remote user's host (which violates the FTP protocol specification but 173closes some security holes). 174.It Fl r 175Put server in read-only mode. 176All commands which may modify the local file system are disabled. 177.It Fl S 178With this option set, 179.Nm 180logs all anonymous file downloads to the file 181.Pa /var/log/ftpd 182when this file exists. 183.It Fl T 184A client may also request a different timeout period; 185the maximum period allowed may be set to 186.Ar timeout 187seconds with the 188.Fl T 189option. 190The default limit is 2 hours. 191.It Fl t 192The inactivity timeout period is set to 193.Ar timeout 194seconds (the default is 15 minutes). 195.It Fl U 196This option instructs ftpd to use data ports in the range of 197.Dv IP_PORTRANGE_DEFAULT 198instead of in the range of 199.Dv IP_PORTRANGE_HIGH . 200Such a change may be useful for some specific firewall configurations; 201see 202.Xr ip 4 203for more information. 204.Pp 205Note that option is a virtual no-op in 206.Fx 5.0 207and above; both port 208ranges are identical by default. 209.It Fl u 210The default file creation mode mask is set to 211.Ar umask , 212which is expected to be an octal numeric value. 213Refer to 214.Xr umask 2 215for details. 216This option may be overridden by 217.Xr login.conf 5 . 218.It Fl v 219A synonym for 220.Fl d . 221.It Fl W 222Do not log FTP sessions to the user accounting database. 223.El 224.Pp 225The file 226.Pa /var/run/nologin 227can be used to disable ftp access. 228If the file exists, 229.Nm 230displays it and exits. 231If the file 232.Pa /etc/ftpwelcome 233exists, 234.Nm 235prints it before issuing the 236.Dq ready 237message. 238If the file 239.Pa /etc/ftpmotd 240exists, 241.Nm 242prints it after a successful login. 243Note the motd file used is the one 244relative to the login environment. 245This means the one in 246.Pa ~ftp/etc 247in the anonymous user's case. 248.Pp 249The ftp server currently supports the following ftp requests. 250The case of the requests is ignored. 251Requests marked [RW] are 252disabled if 253.Fl r 254is specified. 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]" 300.El 301.Pp 302The following non-standard or 303.Ux 304specific commands are supported 305by the 306SITE request. 307.Bl -column Request -offset indent 308.It Sy Request Ta Sy Description 309.It UMASK Ta change umask, e.g. ``SITE UMASK 002'' 310.It IDLE Ta set idle-timer, e.g. ``SITE IDLE 60'' 311.It CHMOD Ta "change mode of a file [RW], e.g. ``SITE CHMOD 755 filename''" 312.It MD5 Ta "report the files MD5 checksum, e.g. ``SITE MD5 filename''" 313.It HELP Ta give help information 314.El 315.Pp 316Note: SITE requests are disabled in case of anonymous logins. 317.Pp 318The remaining ftp requests specified in Internet RFC 959 319are 320recognized, but not implemented. 321MDTM and SIZE are not specified in RFC 959, but will appear in the 322next updated FTP RFC. 323To avoid possible denial-of-service attacks, SIZE requests against 324files larger than 10240 bytes will be denied if the current transfer 325type is ASCII. 326.Pp 327The ftp server will abort an active file transfer only when the 328ABOR 329command is preceded by a Telnet "Interrupt Process" (IP) 330signal and a Telnet "Synch" signal in the command Telnet stream, 331as described in Internet RFC 959. 332If a 333STAT 334command is received during a data transfer, preceded by a Telnet IP 335and Synch, transfer status will be returned. 336.Pp 337The 338.Nm 339utility interprets file names according to the 340.Dq globbing 341conventions used by 342.Xr csh 1 . 343This allows users to utilize the metacharacters 344.Dq Li \&*?[]{}~ . 345.Pp 346The 347.Nm 348utility authenticates users according to six rules. 349.Bl -enum -offset indent 350.It 351The login name must be in the password data base 352and not have a null password. 353In this case a password must be provided by the client before any 354file operations may be performed. 355If the user has an OPIE key, the response from a successful USER 356command will include an OPIE challenge. 357The client may choose to respond with a PASS command giving either 358a standard password or an OPIE one-time password. 359The server will automatically determine which type of 360password it has been given and attempt to authenticate accordingly. 361See 362.Xr opie 4 363for more information on OPIE authentication. 364.It 365The login name must not appear in the file 366.Pa /etc/ftpusers . 367.It 368The login name must not be a member of a group specified in the file 369.Pa /etc/ftpusers . 370Entries in this file interpreted as group names are prefixed by an "at" 371.Ql \&@ 372sign. 373.It 374The user must have a standard shell returned by 375.Xr getusershell 3 . 376.It 377If the user name appears in the file 378.Pa /etc/ftpchroot , 379or the user is a member of a group with a group entry in this file, 380i.e., one prefixed with 381.Ql \&@ , 382the session's root will be changed to the directory specified 383in this file or to the user's login directory by 384.Xr chroot 2 385as for an 386.Dq anonymous 387or 388.Dq ftp 389account (see next item). 390See 391.Xr ftpchroot 5 392for a detailed description of the format of this file. 393This facility may also be triggered by enabling the boolean "ftp-chroot" 394capability in 395.Xr login.conf 5 . 396However, the user must still supply a password. 397This feature is intended as a compromise between a fully anonymous 398account and a fully privileged account. 399The account should also be set up as for an anonymous account. 400.It 401If the user name is 402.Dq anonymous 403or 404.Dq ftp , 405an 406anonymous ftp account must be present in the password 407file (user 408.Dq ftp ) . 409In this case the user is allowed 410to log in by specifying any password (by convention an email address for 411the user should be used as the password). 412When the 413.Fl S 414option is set, all transfers are logged as well. 415.El 416.Pp 417In the last case, 418.Nm 419takes special measures to restrict the client's access privileges. 420The server performs a 421.Xr chroot 2 422to the home directory of the 423.Dq ftp 424user. 425As a special case if the 426.Dq ftp 427user's home directory pathname contains the 428.Pa /./ 429separator, 430.Nm 431uses its left-hand side as the name of the directory to do 432.Xr chroot 2 433to, and its right-hand side to change the current directory to afterwards. 434A typical example for this case would be 435.Pa /usr/local/ftp/./pub . 436In order that system security is not breached, it is recommended 437that the 438.Dq ftp 439subtree be constructed with care, following these rules: 440.Bl -tag -width "~ftp/pub" -offset indent 441.It Pa ~ftp 442Make the home directory owned by 443.Dq root 444and unwritable by anyone. 445.It Pa ~ftp/etc 446Make this directory owned by 447.Dq root 448and unwritable by anyone (mode 555). 449The files pwd.db (see 450.Xr passwd 5 ) 451and 452.Xr group 5 453must be present for the 454.Xr ls 1 455command to be able to produce owner names rather than numbers. 456The password field in 457.Xr passwd 5 458is not used, and should not contain real passwords. 459The file 460.Pa ftpmotd , 461if present, will be printed after a successful login. 462These files should be mode 444. 463.It Pa ~ftp/pub 464This directory and the subdirectories beneath it should be owned 465by the users and groups responsible for placing files in them, 466and be writable only by them (mode 755 or 775). 467They should 468.Em not 469be owned or writable by 470.Dq ftp 471or its group, otherwise guest users 472can fill the drive with unwanted files. 473.El 474.Pp 475If the system has multiple IP addresses, 476.Nm 477supports the idea of virtual hosts, which provides the ability to 478define multiple anonymous ftp areas, each one allocated to a different 479internet address. 480The file 481.Pa /etc/ftphosts 482contains information pertaining to each of the virtual hosts. 483Each host is defined on its own line which contains a number of 484fields separated by whitespace: 485.Bl -tag -offset indent -width hostname 486.It hostname 487Contains the hostname or IP address of the virtual host. 488.It user 489Contains a user record in the system password file. 490As with normal anonymous ftp, this user's access uid, gid and group 491memberships determine file access to the anonymous ftp area. 492The anonymous ftp area (to which any user is chrooted on login) 493is determined by the home directory defined for the account. 494User id and group for any ftp account may be the same as for the 495standard ftp user. 496.It statfile 497File to which all file transfers are logged, which 498defaults to 499.Pa /var/log/ftpd . 500.It welcome 501This file is the welcome message displayed before the server ready 502prompt. 503It defaults to 504.Pa /etc/ftpwelcome . 505.It motd 506This file is displayed after the user logs in. 507It defaults to 508.Pa /etc/ftpmotd . 509.El 510.Pp 511Lines beginning with a '#' are ignored and can be used to include 512comments. 513.Pp 514Defining a virtual host for the primary IP address or hostname 515changes the default for ftp logins to that address. 516The 'user', 'statfile', 'welcome' and 'motd' fields may be left 517blank, or a single hyphen '-' used to indicate that the default 518value is to be used. 519.Pp 520As with any anonymous login configuration, due care must be given 521to setup and maintenance to guard against security related problems. 522.Pp 523The 524.Nm 525utility has internal support for handling remote requests to list 526files, and will not execute 527.Pa /bin/ls 528in either a chrooted or non-chrooted environment. 529The 530.Pa ~/bin/ls 531executable need not be placed into the chrooted tree, nor need the 532.Pa ~/bin 533directory exist. 534.Sh FILES 535.Bl -tag -width ".Pa /var/run/ftpd.pid" -compact 536.It Pa /etc/ftpusers 537List of unwelcome/restricted users. 538.It Pa /etc/ftpchroot 539List of normal users who should be chroot'd. 540.It Pa /etc/ftphosts 541Virtual hosting configuration file. 542.It Pa /etc/ftpwelcome 543Welcome notice. 544.It Pa /etc/ftpmotd 545Welcome notice after login. 546.It Pa /var/run/ftpd.pid 547Default pid file for daemon mode. 548.It Pa /var/run/nologin 549Displayed and access refused. 550.It Pa /var/log/ftpd 551Log file for anonymous transfers. 552.It Pa /var/log/xferlog 553Default place for session logs. 554.El 555.Sh SEE ALSO 556.Xr ftp 1 , 557.Xr umask 2 , 558.Xr getusershell 3 , 559.Xr opie 4 , 560.Xr ftpchroot 5 , 561.Xr login.conf 5 , 562.Xr inetd 8 , 563.Xr syslogd 8 564.Sh HISTORY 565The 566.Nm 567utility appeared in 568.Bx 4.2 . 569IPv6 support was added in WIDE Hydrangea IPv6 stack kit. 570.Sh BUGS 571The server must run as the super-user 572to create sockets with privileged port numbers. 573It maintains 574an effective user id of the logged in user, reverting to 575the super-user only when binding addresses to sockets. 576The 577possible security holes have been extensively 578scrutinized, but are possibly incomplete. 579