NAME

ftpd − file transfer protocol server

SYNOPSIS

/etc/ftpd [ −ttimeout ]

DESCRIPTION

Ftpd is the DARPA Internet File Transfer Protocol server.  It expects to be run by the Internet daemon; see inetd(1M) and inetd.conf(4). Inetd runs ftpd when a service request is received at the port indicated in the “ftp” service specification in /etc/services; see services(4).

The −t option causes ftpd to timeout inactive sessions after timeout seconds.  By default, ftpd does not time out. 

Ftpd currently supports the following commands (case is not distinguished):

Command Description

APPE Append to a file

CDUP A synonym for XCUP; change to parent of current working directory

CWD Change working directory

DELE Delete a file

HELP Give help information

LIST Give long list of files in a directory (“ls -l”)

MKD A synonym for XMKD; make a directory

MODE Specify data transfer mode

NLST Give name list of files in directory (“ls”)

NOOP Do nothing

PASS Specify password

PORT Specify data connection port

PWD A synonym for XPWD; print the current working directory

QUIT Terminate session

RETR Retrieve a file

RMD A synonym for XRMD; remove a directory

RNFR Specify rename-from file name

RNTO Specify rename-to file name

STOR Store a file

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

Ftpd accepts the remaining FTP requests but takes no action. 

Ftpd interprets file names according to the “globbing” conventions used by csh(1). This allows users to utilize the metacharacters * ? [ ] { } ~ .

Ftpd authenticates users in one of two ways:

1) For an ordinary user, the user account name must be in the password database /etc/passwd, and must not have a null password. In addition, the user account name must not appear in the file /etc/ftpusers (see ftpusers(4)).

2) For public access or “anonymous ftp,” an entry must be present in the /etc/passwd file for an account named ftp.  The password field should be “*”, the group membership should be “guest”, and the login shell should be “/bin/false”.  An example entry would look similar to:

ftp:*:500:guest:<ftp_account>:/users/ftp:/bin/false

Then, the user may log into and access the ftp account with the “anonymous” or “ftp” account name and any password (by convention, the client host’s name). If you need more information about setting up this account, see your system administrator. 

DIAGNOSTICS

Ftpd replies to FTP commands to ensure synchronization of requests and actions during file transfers, and to indicate the status of ftpd.  Every command produces at least one reply, although there may be more than one.  A reply consists of a three-digit number, a space, some text, and an end of line.  The number is useful for programs; the text is useful for users.  The number must conform to this standard, but the text can vary. 

The first digit of the message indicates whether the reply is good, bad, or incomplete.  Five values exist for the first digit.  The values and the interpretations of the values are:
 

1 The requested action is being initiated; expect another reply before proceding with a new command. 

2 The requested action is complete. The server is ready for a new request. 

3 The command has been accepted, but the requested action requires more information. 

4 The command was not accepted, the requested action failed, but the error condition is temporary and the action may be requested again. 

5 The command was not accepted, the requested action failed, and the error condition would most likely occur again if the same command sequence is repeated. 
 

The second digit indicates the functional area that the message addresses.  The values of the second digit and the interpretations of these values are:
 

0 Syntax. A message with a 0 for the second digit may indicates that a syntax error occurred. 

1 Information.  A message with a 1 as the second digit indicates that the message is in reply to a request for information. 

2 Connections.  A message with a 2 as the second digit indicates that the message is a reply to a request for control and data connection information. 

3 Authentication and accounting.  A message with a 3 as the second digit indicates that the message is a reply to a login or accounting procedure. 

4 Unspecified as yet. 

5 File system.  A message with a 5 as the second digit indicates that the text following the number is information concerning the status of the server file system. 

The third digit is a finer gradation of meaning of the information supplied by the second digit. 

Several examples of messages are supplied.    Note that ftpd’s replies match the number but not the text.

110 Restart marker reply.  MARK yyyy = mmmm where yyyy is a user process data stream marker, and mmmm is ftpd’s equivalent marker

119 Terminal not available, will try mailbox

120 Service ready in nnn minutes

200 Command okay

211 System status, or system help reply

212 Directory status

230 User logged in, proceed

250 Requested file action okay, completed

331 User name okay, need password

350 Requested file action pending further information

425 Can’t open data connection

451 Requested action aborted: local error in processing

500 Syntax error, command unrecognized or command line too long

530 Not logged in

550 Requested action not taken; file unavailable, not found, no access

WARNINGS

The anonymous account is inherently dangerous to system security and should be avoided. 

DEPENDENCIES

Implemented on the Series 300 and 800 only. 

AUTHOR

UCB (University of California at Berkeley)

SEE ALSO

ftp(1), inetd(1M), inetd.conf(4). 

Hewlett-Packard Company  —  May 11, 2021