The Regents of the University of California. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
must display the following acknowledgement:
This product includes software developed by the University of
California, Berkeley and its contributors.
4. Neither the name of the University nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
@(#)ftpd.8 8.2 (Berkeley) 4/19/94
.Dd April 19, 1994 .Dt FTPD 8 .Os BSD 4.2 .Sh NAME .Nm ftpd .Nd Internet File Transfer Protocol server .Sh SYNOPSIS .Nm ftpd .Op Fl dl .Op Fl D .Op Fl S .Op Fl U .Op Fl T Ar maxtimeout .Op Fl t Ar timeout .Sh DESCRIPTION .Nm Ftpd is the Internet File Transfer Protocol server process. The server uses the .Tn TCP protocol and listens at the port specified in the .Dq ftp service specification; see .Xr services 5 .
p Available options: l -tag -width Ds t Fl d Debugging information is written to the syslog using LOG_FTP. t Fl l Each successful and failed .Xr 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 arguments are also logged. t Fl D With this option set, .Nm ftpd will detach and become a daemon, accepting connections on the FTP port and forking children processes to handle them. This is lower overhead than starting .Nm ftpd from .Xr inetd 8 and is thus useful on busy servers to reduce load. t Fl S With this option set, .Nm ftpd logs all anonymous transfers to the file
a /var/log/ftpd when this file exists. . t Fl U In previous versions of .Nm ftpd , when a passive mode client requested a data connection to the server, the server would use data ports in the range 1024..4999. Now, by default, the server will use data ports in the range 40000..44999. Specifying this option will revert to the old behavior. t Fl T A client may also request a different timeout period; the maximum period allowed may be set to .Ar timeout seconds with the .Fl T option. The default limit is 2 hours. t Fl t The inactivity timeout period is set to .Ar timeout seconds (the default is 15 minutes). .El
p The file
a /etc/nologin can be used to disable ftp access. If the file exists, .Nm displays it and exits. If the file
a /etc/ftpwelcome exists, .Nm prints it before issuing the .Dq ready message. If the file
a /etc/ftpmotd exists, .Nm prints it after a successful login.
p The ftp server currently supports the following ftp requests. The case of the requests is ignored. l -column "Request" -offset indent t Request Ta "Description" t ABOR Ta "abort previous command" t ACCT Ta "specify account (ignored)" t ALLO Ta "allocate storage (vacuously)" t APPE Ta "append to a file" t CDUP Ta "change to parent of current working directory" t CWD Ta "change working directory" t DELE Ta "delete a file" t HELP Ta "give help information" t LIST Ta "give list files in a directory" Pq Dq Li "ls -lgA" t MKD Ta "make a directory" t MDTM Ta "show last modification time of file" t MODE Ta "specify data transfer" Em mode t NLST Ta "give name list of files in directory" t NOOP Ta "do nothing" t PASS Ta "specify password" t PASV Ta "prepare for server-to-server transfer" t PORT Ta "specify data connection port" t PWD Ta "print the current working directory" t QUIT Ta "terminate session" t REST Ta "restart incomplete transfer" t RETR Ta "retrieve a file" t RMD Ta "remove a directory" t RNFR Ta "specify rename-from file name" t RNTO Ta "specify rename-to file name" t SITE Ta "non-standard commands (see next section)" t SIZE Ta "return size of file" t STAT Ta "return status of server" t STOR Ta "store a file" t STOU Ta "store a file with a unique name" t STRU Ta "specify data transfer" Em structure t SYST Ta "show operating system type of server system" t TYPE Ta "specify data transfer" Em type t USER Ta "specify user name" t XCUP Ta "change to parent of current working directory (deprecated)" t XCWD Ta "change working directory (deprecated)" t XMKD Ta "make a directory (deprecated)" t XPWD Ta "print the current working directory (deprecated)" t XRMD Ta "remove a directory (deprecated)" .El
p The following non-standard or .Tn UNIX specific commands are supported by the SITE request.
p l -column Request -offset indent t Sy Request Ta Sy Description t UMASK Ta change umask, e.g. ``SITE UMASK 002'' t IDLE Ta set idle-timer, e.g. ``SITE IDLE 60'' t CHMOD Ta change mode of a file, e.g. ``SITE CHMOD 755 filename'' t HELP Ta give help information. .El
p 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.
p The ftp server will abort an active file transfer only when the ABOR command 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.
p .Nm Ftpd interprets file names according to the .Dq globbing conventions used by .Xr csh 1 . This allows users to utilize the metacharacters .Dq Li *?[]{}~ .
p .Nm Ftpd authenticates users according to three rules.
p l -enum -offset indent t The login name must be in the password data base,
a /etc/passwd , and not have a null password. In this case a password must be provided by the client before any file operations may be performed. t The login name must not appear in the file
a /etc/ftpusers . t The user must have a standard shell returned by .Xr getusershell 3 . t If the user name is .Dq anonymous or .Dq ftp , an anonymous ftp account must be present in the password file (user .Dq 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 .Fl S option is set, all transfers are logged as well. .El
p In the last case, .Nm ftpd takes special measures to restrict the client's access privileges. The server performs a .Xr chroot 2 to the home directory of the .Dq ftp user. In order that system security is not breached, it is recommended that the .Dq ftp subtree be constructed with care, following these rules: l -tag -width "~ftp/pub" -offset indent t Pa ~ftp Make the home directory owned by .Dq root and unwritable by anyone. t Pa ~ftp/bin Make this directory owned by .Dq root and unwritable by anyone (mode 555). The program .Xr ls 1 must be present to support the list command. This program should be mode 111. t Pa ~ftp/etc Make this directory owned by .Dq root and unwritable by anyone (mode 555). The files .Xr passwd 5 and .Xr group 5 must be present for the .Xr ls command to be able to produce owner names rather than numbers. The password field in .Xr passwd is not used, and should not contain real passwords. The file
a ftpmotd , if present, will be printed after a successful login. These files should be mode 444. t Pa ~ftp/pub Make this directory mode 777 and owned by .Dq ftp . Guests can then place files which are to be accessible via the anonymous account in this directory. .El .Sh FILES l -tag -width /etc/ftpwelcome -compact t Pa /etc/ftpusers List of unwelcome/restricted users. t Pa /etc/ftpwelcome Welcome notice. t Pa /etc/ftpmotd Welcome notice after login. t Pa /etc/nologin Displayed and access refused. t Pa /var/log/ftpd Log file for anonymous transfers. .El .Sh SEE ALSO .Xr ftp 1 , .Xr getusershell 3 , .Xr inetd 8 , .Xr syslogd 8 .Sh BUGS 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 possibly incomplete. .Sh HISTORY The .Nm command appeared in x 4.2 .