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 April 20, 2007 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.Pp 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 315.El 316.Pp 317Note: SITE requests are disabled in case of anonymous logins. 318.Pp 319The remaining ftp requests specified in Internet RFC 959 320are 321recognized, but not implemented. 322MDTM and SIZE are not specified in RFC 959, but will appear in the 323next updated FTP RFC. 324To avoid possible denial-of-service attacks, SIZE requests against 325files larger than 10240 bytes will be denied if the current transfer 326type is ASCII. 327.Pp 328The ftp server will abort an active file transfer only when the 329ABOR 330command is preceded by a Telnet "Interrupt Process" (IP) 331signal and a Telnet "Synch" signal in the command Telnet stream, 332as described in Internet RFC 959. 333If a 334STAT 335command is received during a data transfer, preceded by a Telnet IP 336and Synch, transfer status will be returned. 337.Pp 338The 339.Nm 340utility interprets file names according to the 341.Dq globbing 342conventions used by 343.Xr csh 1 . 344This allows users to utilize the metacharacters 345.Dq Li \&*?[]{}~ . 346.Pp 347The 348.Nm 349utility authenticates users according to six rules. 350.Pp 351.Bl -enum -offset indent 352.It 353The login name must be in the password data base 354and not have a null password. 355In this case a password must be provided by the client before any 356file operations may be performed. 357If the user has an OPIE key, the response from a successful USER 358command will include an OPIE challenge. 359The client may choose to respond with a PASS command giving either 360a standard password or an OPIE one-time password. 361The server will automatically determine which type of 362password it has been given and attempt to authenticate accordingly. 363See 364.Xr opie 4 365for more information on OPIE authentication. 366.It 367The login name must not appear in the file 368.Pa /etc/ftpusers . 369.It 370The login name must not be a member of a group specified in the file 371.Pa /etc/ftpusers . 372Entries in this file interpreted as group names are prefixed by an "at" 373.Ql \&@ 374sign. 375.It 376The user must have a standard shell returned by 377.Xr getusershell 3 . 378.It 379If the user name appears in the file 380.Pa /etc/ftpchroot , 381or the user is a member of a group with a group entry in this file, 382i.e., one prefixed with 383.Ql \&@ , 384the session's root will be changed to the directory specified 385in this file or to the user's login directory by 386.Xr chroot 2 387as for an 388.Dq anonymous 389or 390.Dq ftp 391account (see next item). 392See 393.Xr ftpchroot 5 394for a detailed description of the format of this file. 395This facility may also be triggered by enabling the boolean "ftp-chroot" 396capability in 397.Xr login.conf 5 . 398However, the user must still supply a password. 399This feature is intended as a compromise between a fully anonymous 400account and a fully privileged account. 401The account should also be set up as for an anonymous account. 402.It 403If the user name is 404.Dq anonymous 405or 406.Dq ftp , 407an 408anonymous ftp account must be present in the password 409file (user 410.Dq ftp ) . 411In this case the user is allowed 412to log in by specifying any password (by convention an email address for 413the user should be used as the password). 414When the 415.Fl S 416option is set, all transfers are logged as well. 417.El 418.Pp 419In the last case, 420.Nm 421takes special measures to restrict the client's access privileges. 422The server performs a 423.Xr chroot 2 424to the home directory of the 425.Dq ftp 426user. 427As a special case if the 428.Dq ftp 429user's home directory pathname contains the 430.Pa /./ 431separator, 432.Nm 433uses its left-hand side as the name of the directory to do 434.Xr chroot 2 435to, and its right-hand side to change the current directory to afterwards. 436A typical example for this case would be 437.Pa /usr/local/ftp/./pub . 438In order that system security is not breached, it is recommended 439that the 440.Dq ftp 441subtree be constructed with care, following these rules: 442.Bl -tag -width "~ftp/pub" -offset indent 443.It Pa ~ftp 444Make the home directory owned by 445.Dq root 446and unwritable by anyone. 447.It Pa ~ftp/etc 448Make this directory owned by 449.Dq root 450and unwritable by anyone (mode 555). 451The files pwd.db (see 452.Xr passwd 5 ) 453and 454.Xr group 5 455must be present for the 456.Xr ls 1 457command to be able to produce owner names rather than numbers. 458The password field in 459.Xr passwd 5 460is not used, and should not contain real passwords. 461The file 462.Pa ftpmotd , 463if present, will be printed after a successful login. 464These files should be mode 444. 465.It Pa ~ftp/pub 466This directory and the subdirectories beneath it should be owned 467by the users and groups responsible for placing files in them, 468and be writable only by them (mode 755 or 775). 469They should 470.Em not 471be owned or writable by 472.Dq ftp 473or its group, otherwise guest users 474can fill the drive with unwanted files. 475.El 476.Pp 477If the system has multiple IP addresses, 478.Nm 479supports the idea of virtual hosts, which provides the ability to 480define multiple anonymous ftp areas, each one allocated to a different 481internet address. 482The file 483.Pa /etc/ftphosts 484contains information pertaining to each of the virtual hosts. 485Each host is defined on its own line which contains a number of 486fields separated by whitespace: 487.Bl -tag -offset indent -width hostname 488.It hostname 489Contains the hostname or IP address of the virtual host. 490.It user 491Contains a user record in the system password file. 492As with normal anonymous ftp, this user's access uid, gid and group 493memberships determine file access to the anonymous ftp area. 494The anonymous ftp area (to which any user is chrooted on login) 495is determined by the home directory defined for the account. 496User id and group for any ftp account may be the same as for the 497standard ftp user. 498.It statfile 499File to which all file transfers are logged, which 500defaults to 501.Pa /var/log/ftpd . 502.It welcome 503This file is the welcome message displayed before the server ready 504prompt. 505It defaults to 506.Pa /etc/ftpwelcome . 507.It motd 508This file is displayed after the user logs in. 509It defaults to 510.Pa /etc/ftpmotd . 511.El 512.Pp 513Lines beginning with a '#' are ignored and can be used to include 514comments. 515.Pp 516Defining a virtual host for the primary IP address or hostname 517changes the default for ftp logins to that address. 518The 'user', 'statfile', 'welcome' and 'motd' fields may be left 519blank, or a single hyphen '-' used to indicate that the default 520value is to be used. 521.Pp 522As with any anonymous login configuration, due care must be given 523to setup and maintenance to guard against security related problems. 524.Pp 525The 526.Nm 527utility has internal support for handling remote requests to list 528files, and will not execute 529.Pa /bin/ls 530in either a chrooted or non-chrooted environment. 531The 532.Pa ~/bin/ls 533executable need not be placed into the chrooted tree, nor need the 534.Pa ~/bin 535directory exist. 536.Sh FILES 537.Bl -tag -width ".Pa /var/run/ftpd.pid" -compact 538.It Pa /etc/ftpusers 539List of unwelcome/restricted users. 540.It Pa /etc/ftpchroot 541List of normal users who should be chroot'd. 542.It Pa /etc/ftphosts 543Virtual hosting configuration file. 544.It Pa /etc/ftpwelcome 545Welcome notice. 546.It Pa /etc/ftpmotd 547Welcome notice after login. 548.It Pa /var/run/ftpd.pid 549Default pid file for daemon mode. 550.It Pa /var/run/nologin 551Displayed and access refused. 552.It Pa /var/log/ftpd 553Log file for anonymous transfers. 554.It Pa /var/log/xferlog 555Default place for session logs. 556.El 557.Sh SEE ALSO 558.Xr ftp 1 , 559.Xr umask 2 , 560.Xr getusershell 3 , 561.Xr opie 4 , 562.Xr ftpchroot 5 , 563.Xr login.conf 5 , 564.Xr inetd 8 , 565.Xr syslogd 8 566.Sh HISTORY 567The 568.Nm 569utility appeared in 570.Bx 4.2 . 571IPv6 support was added in WIDE Hydrangea IPv6 stack kit. 572.Sh BUGS 573The server must run as the super-user 574to create sockets with privileged port numbers. 575It maintains 576an effective user id of the logged in user, reverting to 577the super-user only when binding addresses to sockets. 578The 579possible security holes have been extensively 580scrutinized, but are possibly incomplete. 581