FTPD(8) System Manager's Manual FTPD(8)
ftpd, in.ftpd, setup.anonftp - DARPA Internet File Transfer Protocol server
ftp stream tcp nowait root /usr/sbin/in.ftpd in.ftpd
tcpd ftp /usr/sbin/in.ftpd
Ftpd is the DARPA Internet File Transfer Prototocol server process. The server uses the TCP protocol and listens at the port specified in
the ``ftp'' service specification; see services(5).
The ftp server currently supports the following ftp requests; case is not distinguished.
ABOR abort previous command
ACCT specify account (ignored)
ALLO allocate storage (vacuously)
APPE append to a file
CDUP change to parent of current working directory
CWD change working directory
DELE delete a file
HELP give help information
LIST give list files in a directory (``ls -lA'')
MKD make a directory
MODE specify data transfer mode
NLST give name list of files in directory (``ls'')
NOOP do nothing
PASS specify password
PASV prepare for server-to-server transfer
PORT specify data connection port
PWD print the current working directory
QUIT terminate session
RETR retrieve a file
RMD remove a directory
RNFR specify rename-from file name
RNTO specify rename-to file name
STOR store a file
STOU store a file with a unique name
STRU specify data transfer structure
TYPE specify data transfer type
USER specify user name
XCUP change to parent of current working directory
XCWD change working directory
XMKD make a directory
XPWD print the current working directory
XRMD remove a directory
The remaining ftp requests specified in Internet RFC 959 are recognized, but not implemented.
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.
Ftpd interprets file names according to the ``globbing'' conventions used by csh(1). This allows users to utilize the metacharacters
Ftpd authenticates users according to three rules.
1) The user name must be in the password data base, /etc/passwd, and not have a null password. In this case a password must be pro-
vided by the client before any file operations may be performed.
2) The user name must not appear in the file /etc/ftpusers.
3) If the user name is ``anonymous'' or ``ftp'', an anonymous ftp account must be present in the password file (user ``ftp''). In this
case the user is allowed to log in by specifying any password (by convention this is given as the client host's name).
In the last case, ftpd takes special measures to restrict the client's access privileges. The server performs a chroot(2) command to the
home directory of the ``ftp'' user. In order that system security is not breached, it is recommended that the ``ftp'' subtree be con-
structed with care; the following rules are recommended.
~ftp) Make the home directory owned by ``ftp'' and unwritable by anyone.
Make this directory owned by the super-user and unwritable by anyone. The program ls(1) must be present to support the list com-
mands. This program should have mode 111.
Make this directory owned by the super-user and unwritable by anyone. The files passwd(5) and group(5) must be present for the ls
command to work properly. These files should be mode 444.
Make this directory mode 755 and owned by the super-user. Create directories in it owned by users if those users want to manage an
anonymous ftp directory.
Optionally create this directory for anonymous uploads. Make it mode 777. The FTP daemon will create files with mode 266, so
remote users can write a file, but only local users can do something with it.
The script setup.anonftp can be used to create or check an anonymous FTP tree.
The anonymous account is inherently dangerous and should avoided when possible.