1.\" $NetBSD: ftpd.8,v 1.7 1995/04/11 02:44:53 cgd Exp $ 2.\" 3.\" Copyright (c) 1985, 1988, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)ftpd.8 8.2 (Berkeley) 4/19/94 35.\" 36.Dd April 19, 1997 37.Dt FTPD 8 38.Os BSD 4.2 39.Sh NAME 40.Nm ftpd 41.Nd Internet File Transfer Protocol server 42.Sh SYNOPSIS 43.Nm 44.Op Fl a Ar authmode 45.Op Fl dilvU 46.Op Fl g Ar umask 47.Op Fl p Ar port 48.Op Fl T Ar maxtimeout 49.Op Fl t Ar timeout 50.Op Fl u Ar default umask 51.Op Fl B | Fl -builtin-ls 52.Op Fl -good-chars= Ns Ar string 53.Sh DESCRIPTION 54.Nm Ftpd 55is the 56Internet File Transfer Protocol 57server process. The server uses the 58.Tn TCP 59protocol 60and listens at the port specified in the 61.Dq ftp 62service specification; see 63.Xr services 5 . 64.Pp 65Available options: 66.Bl -tag -width Ds 67.It Fl a 68Select the level of authentication required. Kerberised login can not 69be turned off. The default is to only allow kerberised login. Other 70possibilities can be turned on by giving a string of comma separated 71flags as argument to 72.Fl a . 73Recognised flags are: 74.Bl -tag -width plain 75.It Ar plain 76Allow logging in with plaintext password. The password can be a(n) OTP 77or an ordinary password. 78.It Ar otp 79Same as 80.Ar plain , 81but only OTP is allowed. 82.It Ar ftp 83Allow anonymous login. 84.El 85.Pp 86The following combination modes exists for backwards compatibility: 87.Bl -tag -width plain 88.It Ar none 89Same as 90.Ar plain,ftp . 91.It Ar safe 92Same as 93.Ar ftp . 94.It Ar user 95Ignored. 96.El 97.It Fl d 98Debugging information is written to the syslog using LOG_FTP. 99.It Fl g 100Anonymous users will get a umask of 101.Ar umask . 102.It Fl i 103Open a socket and wait for a connection. This is mainly used for 104debugging when ftpd isn't started by inetd. 105.It Fl l 106Each successful and failed 107.Xr ftp 1 108session is logged using syslog with a facility of LOG_FTP. 109If this option is specified twice, the retrieve (get), store (put), append, 110delete, make directory, remove directory and rename operations and 111their filename arguments are also logged. 112.It Fl p 113Use 114.Ar port 115(a service name or number) instead of the default 116.Ar ftp/tcp . 117.It Fl T 118A client may also request a different timeout period; 119the maximum period allowed may be set to 120.Ar timeout 121seconds with the 122.Fl T 123option. 124The default limit is 2 hours. 125.It Fl t 126The inactivity timeout period is set to 127.Ar timeout 128seconds (the default is 15 minutes). 129.It Fl u 130Set the initial umask to something else than the default 027. 131.It Fl U 132In previous versions of 133.Nm ftpd , 134when a passive mode client requested a data connection to the server, the 135server would use data ports in the range 1024..4999. Now, by default, 136if the system supports the IP_PORTRANGE socket option, the server will 137use data ports in the range 49152..65535. Specifying this option will 138revert to the old behavior. 139.It Fl v 140Verbose mode. 141.It Xo 142.Fl B Ns , 143.Fl -builtin-ls 144.Xc 145use built-in ls to list files 146.It Xo 147.Fl -good-chars= Ns Ar string 148.Xc 149allowed anonymous upload filename chars 150.El 151.Pp 152The file 153.Pa /etc/nologin 154can be used to disable ftp access. 155If the file exists, 156.Nm 157displays it and exits. 158If the file 159.Pa /etc/ftpwelcome 160exists, 161.Nm 162prints it before issuing the 163.Dq ready 164message. 165If the file 166.Pa /etc/motd 167exists, 168.Nm 169prints it after a successful login. 170.Pp 171The ftp server currently supports the following ftp requests. 172The case of the requests is ignored. 173.Bl -column "Request" -offset indent 174.It Request Ta "Description" 175.It ABOR Ta "abort previous command" 176.It ACCT Ta "specify account (ignored)" 177.It ALLO Ta "allocate storage (vacuously)" 178.It APPE Ta "append to a file" 179.It CDUP Ta "change to parent of current working directory" 180.It CWD Ta "change working directory" 181.It DELE Ta "delete a file" 182.It HELP Ta "give help information" 183.It LIST Ta "give list files in a directory" Pq Dq Li "ls -lgA" 184.It MKD Ta "make a directory" 185.It MDTM Ta "show last modification time of file" 186.It MODE Ta "specify data transfer" Em mode 187.It NLST Ta "give name list of files in directory" 188.It NOOP Ta "do nothing" 189.It PASS Ta "specify password" 190.It PASV Ta "prepare for server-to-server transfer" 191.It PORT Ta "specify data connection port" 192.It PWD Ta "print the current working directory" 193.It QUIT Ta "terminate session" 194.It REST Ta "restart incomplete transfer" 195.It RETR Ta "retrieve a file" 196.It RMD Ta "remove a directory" 197.It RNFR Ta "specify rename-from file name" 198.It RNTO Ta "specify rename-to file name" 199.It SITE Ta "non-standard commands (see next section)" 200.It SIZE Ta "return size of file" 201.It STAT Ta "return status of server" 202.It STOR Ta "store a file" 203.It STOU Ta "store a file with a unique name" 204.It STRU Ta "specify data transfer" Em structure 205.It SYST Ta "show operating system type of server system" 206.It TYPE Ta "specify data transfer" Em type 207.It USER Ta "specify user name" 208.It XCUP Ta "change to parent of current working directory (deprecated)" 209.It XCWD Ta "change working directory (deprecated)" 210.It XMKD Ta "make a directory (deprecated)" 211.It XPWD Ta "print the current working directory (deprecated)" 212.It XRMD Ta "remove a directory (deprecated)" 213.El 214.Pp 215The following commands are specified by RFC2228. 216.Bl -column Request -offset indent 217.It AUTH Ta "authentication/security mechanism" 218.It ADAT Ta "authentication/security data" 219.It PROT Ta "data channel protection level" 220.It PBSZ Ta "protection buffer size" 221.It MIC Ta "integrity protected command" 222.It CONF Ta "confidentiality protected command" 223.It ENC Ta "privacy protected command" 224.It CCC Ta "clear command channel" 225.El 226.Pp 227The following non-standard or 228.Tn UNIX 229specific commands are supported 230by the 231SITE request. 232.Pp 233.Bl -column Request -offset indent 234.It UMASK Ta change umask, (e.g. 235.Ic "SITE UMASK 002" ) 236.It IDLE Ta set idle-timer, (e.g. 237.Ic "SITE IDLE 60" ) 238.It CHMOD Ta change mode of a file (e.g. 239.Ic "SITE CHMOD 755 filename" ) 240.It FIND Ta quickly find a specific file with GNU 241.Xr locate 1 . 242.It HELP Ta give help information. 243.El 244.Pp 245The following Kerberos related site commands are understood. 246.Bl -column Request -offset indent 247.It KAUTH Ta obtain remote tickets. 248.It KLIST Ta show remote tickets 249.El 250.Pp 251The remaining ftp requests specified in Internet RFC 959 252are 253recognized, but not implemented. 254MDTM and SIZE are not specified in RFC 959, but will appear in the 255next updated FTP RFC. 256.Pp 257The ftp server will abort an active file transfer only when the 258ABOR 259command is preceded by a Telnet "Interrupt Process" (IP) 260signal and a Telnet "Synch" signal in the command Telnet stream, 261as described in Internet RFC 959. 262If a 263STAT 264command is received during a data transfer, preceded by a Telnet IP 265and Synch, transfer status will be returned. 266.Pp 267.Nm Ftpd 268interprets file names according to the 269.Dq globbing 270conventions used by 271.Xr csh 1 . 272This allows users to utilize the metacharacters 273.Dq Li \&*?[]{}~ . 274.Pp 275.Nm Ftpd 276authenticates users according to these rules. 277.Pp 278.Bl -enum -offset indent 279.It 280If Kerberos authentication is used, the user must pass valid tickets 281and the principal must be allowed to login as the remote user. 282.It 283The login name must be in the password data base, and not have a null 284password (if kerberos is used the password field is not checked). In 285this case a password must be provided by the client before any file 286operations may be performed. If the user has an OTP key, the response 287from a successful USER command will include an OTP challenge. The 288client may choose to respond with a PASS command giving either a 289standard password or an OTP one-time password. The server will 290automatically determine which type of password it has been given and 291attempt to authenticate accordingly. See 292.Xr otp 1 293for more information on OTP authentication. 294.It 295The login name must not appear in the file 296.Pa /etc/ftpusers . 297.It 298The user must have a standard shell returned by 299.Xr getusershell 3 . 300.It 301If the user name appears in the file 302.Pa /etc/ftpchroot 303the session's root will be changed to the user's login directory by 304.Xr chroot 2 305as for an 306.Dq anonymous 307or 308.Dq ftp 309account (see next item). However, the user must still supply a password. 310This feature is intended as a compromise between a fully anonymous account 311and a fully privileged account. The account should also be set up as for an 312anonymous account. 313.It 314If the user name is 315.Dq anonymous 316or 317.Dq ftp , 318an 319anonymous ftp account must be present in the password 320file (user 321.Dq ftp ) . 322In this case the user is allowed 323to log in by specifying any password (by convention an email address for 324the user should be used as the password). 325.El 326.Pp 327In the last case, 328.Nm ftpd 329takes special measures to restrict the client's access privileges. 330The server performs a 331.Xr chroot 2 332to the home directory of the 333.Dq ftp 334user. 335In order that system security is not breached, it is recommended 336that the 337.Dq ftp 338subtree be constructed with care, consider following these guidelines 339for anonymous ftp. 340.Pp 341In general all files should be owned by 342.Dq root , 343and have non-write permissions (644 or 755 depending on the kind of 344file). No files should be owned or writable by 345.Dq ftp 346(possibly with exception for the 347.Pa ~ftp/incoming , 348as specified below). 349.Bl -tag -width "~ftp/pub" -offset indent 350.It Pa ~ftp 351The 352.Dq ftp 353homedirectory should be owned by root. 354.It Pa ~ftp/bin 355The directory for external programs (such as 356.Xr ls 1 ) . 357These programs must either be statically linked, or you must setup an 358environment for dynamic linking when running chrooted. 359These programs will be used if present: 360.Bl -tag -width "locate" -offset indent 361.It ls 362Used when listing files. 363.It compress 364When retrieving a filename that ends in 365.Pa .Z , 366and that file isn't present, 367.Nm 368will try to find the filename without 369.Pa .Z 370and compress it on the fly. 371.It gzip 372Same as compress, just with files ending in 373.Pa .gz . 374.It gtar 375Enables retrieval of whole directories as files ending in 376.Pa .tar . 377Can also be combined with compression. You must use GNU Tar (or some 378other that supports the 379.Fl z 380and 381.Fl Z 382flags). 383.It locate 384Will enable ``fast find'' with the 385.Ic SITE FIND 386command. You must also create a 387.Pa locatedb 388file in 389.Pa ~ftp/etc . 390.El 391.It Pa ~ftp/etc 392If you put copies of the 393.Xr passwd 5 394and 395.Xr group 5 396files here, ls will be able to produce owner names rather than 397numbers. Remember to remove any passwords from these files. 398.Pp 399The file 400.Pa motd , 401if present, will be printed after a successful login. 402.It Pa ~ftp/dev 403Put a copy of 404.Xr /dev/null 7 405here. 406.It Pa ~ftp/pub 407Traditional place to put whatever you want to make public. 408.El 409.Pp 410If you want guests to be able to upload files, create a 411.Pa ~ftp/incoming 412directory owned by 413.Dq root , 414and group 415.Dq ftp 416with mode 730 (make sure 417.Dq ftp 418is member of group 419.Dq ftp ) . 420The following restrictions apply to anonymous users: 421.Bl -bullet 422.It 423Directories created will have mode 700. 424.It 425Uploaded files will be created with an umask of 777, if not changed 426with the 427.Fl g 428option. 429.It 430These command are not accessible: 431.Ic DELE , RMD , RNTO , RNFR , 432.Ic SITE UMASK , 433and 434.Ic SITE CHMOD . 435.It 436Filenames must start with an alpha-numeric character, and consist of 437alpha-numeric characters or any of the following: 438.Li \&+ 439(plus), 440.Li \&- 441(minus), 442.Li \&= 443(equal), 444.Li \&_ 445(underscore), 446.Li \&. 447(period), and 448.Li \&, 449(comma). 450.El 451.Sh FILES 452.Bl -tag -width /etc/ftpwelcome -compact 453.It Pa /etc/ftpusers 454Access list for users. 455.It Pa /etc/ftpchroot 456List of normal users who should be chroot'd. 457.It Pa /etc/ftpwelcome 458Welcome notice. 459.It Pa /etc/motd 460Welcome notice after login. 461.It Pa /etc/nologin 462Displayed and access refused. 463.It Pa ~/.klogin 464Login access for Kerberos. 465.El 466.Sh SEE ALSO 467.Xr ftp 1 , 468.Xr otp 1 , 469.Xr getusershell 3 , 470.Xr ftpusers 5 , 471.Xr syslogd 8 472.Sh STANDARDS 473.Bl -tag -compact -width "RFC 1938" 474.It Cm RFC 959 475FTP PROTOCOL SPECIFICATION 476.It Cm RFC 1938 477OTP Specification 478.It Cm RFC 2228 479FTP Security Extensions. 480.El 481.Sh BUGS 482The server must run as the super-user 483to create sockets with privileged port numbers. It maintains 484an effective user id of the logged in user, reverting to 485the super-user only when binding addresses to sockets. The 486possible security holes have been extensively 487scrutinized, but are possibly incomplete. 488.Sh HISTORY 489The 490.Nm 491command appeared in 492.Bx 4.2 . 493