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NAME

na_ftpd - File transfer protocol daemon

SYNOPSIS

options ftpd.enable on

DESCRIPTION

FTPD is the Internet File Transfer Protocol (FTP) server process. The server uses the TCP protocol and listens at the well-known port (21) for ftp.

Requests
The FTP server currently supports the following FTP requests; case is not distinguished.

ABOR
Aborts previous command.

ACCT
Specifies account (ignored).

ALLO
Allocates storage (without using space).

APPE
Appends to a file.

AUTH
Security mechanism

CCC
Clears command channel.

CDUP
Changes to parent of current working directory.

CWD
Changes working directory.

DELE
Deletes a file.

EPRT
Specifies data connection port (IPv4 or IPv6).

EPSV
Prepares for passive mode transfer (IPv4 or IPv6).

HELP
Gives help information.

LIST
Gives list files in a directory (ls -lg).

MKD
Makes a directory.

MODE
Specifies data transfer. mode

NLST
Gives name list of files in directory (ls).

NOOP
Does nothing.

PASS
Specifies password.

PASV
Prepares for server-to-server transfer.

PBSZ
Protection buffer size

PORT
Specifies data connection port.

PROT
Data channel protection level.

PWD
Prints the current working directory.

QUIT
Terminates session.

RETR
Retrieves a file.

RMD
Removes a directory.

RNFR
Specifies rename-from file name.

RNTO
Specifies rename-to file name.

STOR
Stores a file.

STOU
Stores a file with a unique name.

STRU
Specifies data transfer structure.

TYPE
Specifies data transfer type.

USER
Specifies user name.

XCUP
Changes to parent of current working directory.

XCWD
Changes working directory.

XMKD
Makes a directory.

XPWD
Prints the current working directory.

XRMD
Removes a directory.

The remaining FTP requests specified in RFC 959 are recognized, but not implemented.

The FTP server aborts 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 RFC 959.

The FTP server interprets file names according to the "globbing" conventions used by sh(1). This enables users to use the metacharacters: * ? [ ] { } ~.

The FTP server authenticates users according to two rules:

First, the user name must be in the password database, /etc/passwd, and have a password that is not NULL. A password must always be provided by the client before any file operations can be performed.

Second, if the user name is "anonymous" or "ftp", an entry for the user name ftp must be present in the password and shadow files. The user is then allowed to log in by specifying any password -- by convention this is given as the user's email address (such as user@mycompany.com). Do not specify a valid shell in the password entry of the ftp user, and do not give it a valid password (use NP in the encrypted password field of the shadow file).

For anonymous ftp users, the FTP server 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.

DIAGNOSTICS

Ftpd logs all commands to the /etc/log/ftp.cmd file.

Ftpd logs all transfers to the /etc/log/ftp.xfer file.

FILES

/etc/passwd
/etc/log/ftp.cmd
/etc/log/ftp.xfer

SEE ALSO

Postel, Jon, and Joyce Reynolds, File Transfer Protocol (FTP), RFC 959, Network Information Center, SRI International, Menlo Park, Calif., October 1985.

Ford-Hutchison, Securing FTP with TLS, RFC 4217, IBM UK Ltd. October 2005.


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