FTP

The File Transfer Protocol (FTP) provides the basic elements of file sharing between hosts. FTP uses TCP to create a virtual connection for control information and then creates a separate TCP connection for data transfers.

Commands:

Command	Description	References
ABOR	Abort a file transfer.
ACCT <account>	Send account information.
ADAT	Authentication/Security Data.	RFC 2228
ALLO <bytes>	Allocate.
APPE <filename>	Append to a remote file.
AUTH	Authentication/Security Mechanism.	RFC 2228
CCC	Clear Command Channel.	RFC 2228
CDUP <dir path>	Change to parent directory.	RFC 959
CONF	Confidentiality Protected Command.	RFC 2228
CWD <dir path>	Change working directory.	RFC 697
DELE <filename>	Delete a remote file.
ENC	Privacy Protected Command.	RFC 2228
EPRT	Extended Data port.	RFC 2428
EPSV	Extended Passive.	RFC 2428
FEAT	Feature.	RFC 2389
HELP <command>	Return help on using the server.
HOST <host>	Set virtual host name
LANG	Language negotiation.	RFC 2640
LIST <name>	List long dir/file-information.
LPRT	Long data port.	RFC 1639
LPSV	Long passive.	RFC 1639
MDTM	Return the modification time of a file.
MIC	Integrity Protected Command.	RFC 2228
MKD <directory>	Make a remote directory.	RFC 959
MLSD <directory>	Name list of remote directory.
MODE <mode>	Set transfer mode. (S=stream, B=block, C=compressed)
NLST <directory>	Name list of remote directory.
NOOP	No operation.
OPTS	Options.	RFC 2389
PASS <password>	Send password.
PASV	Enter passive mode.
PBSZ	Protection Buffer Size.	RFC 2228
PORT <address>	Open a Data port (h1,h2,h3,h4,p1,p2).
PROT	Data Channel Protection Level.	RFC 2228
PWD	Print working directory.	RFC 959
QUIT	Logout (terminate the connection).
REIN	Reinitialize the connection.
REST <offset>	Restart.
RETR <filename>	Retrieve a remote file.
RMD <directory>	Remove a remote directory.	RFC 959
RNFR <old path>	Rename from.
RNTO <new path>	Rename to.
SITE <params>	Site parameters (site-specific commands).
SIZE <filename>	Return the size of a file .
SMNT <pathname>	Structure mount.	RFC 959
STAT <directory>	Return server status.
STOR <filename>	Store a file on the remote host.
STOU <filename>	Store a file unique.	RFC 959
STRU <type>	Set file transfer structure (F=file, R=record, P=page).
SYST	return system type.	RFC 959
TYPE <data type>	Set transfer type (A=ASCII, E=EBCDIC, I=binary).
USER <username>	Send user name for system log-in.
XCUP	Change to the parent of the current working directory.	RFC 775
XMKD	Make a directory.	RFC 775
XPWD	Print the current working directory.	RFC 775
XRCP	extension to FTP mail (Now incorporated into SMTP, RFC 788)	RFC 743
XRMD	Remove the directory.	RFC 775
XRSQ	extension to FTP mail (Now incorporated into SMTP, RFC 788)	RFC 743
XSEM	Send, Mail if cannot.	RFC 737
XSEN	Send to terminal.	RFC 737

FTP reply code format:

Code	Description
1yz	Positive Preliminary reply.
2yz	Positive Completion reply.
3yz	Positive Intermediate reply.
4yz	Transient Negative Completion reply.
5yz	Permanent Negative Completion reply.
x0z	Syntax. These replies refer to syntax errors, syntactically correct commands that don't fit any functional category, unimplemented or superfluous commands.
x1z	Information. These are replies to requests for information, such as status or help.
x2z	Connections. Replies referring to the control and data connections.
x3z	Authentication and accounting. Replies for the login process and accounting procedures.
x4z	File system. These replies indicate the status of the Server file system vis-a-vis the requested transfer or other file system action.
x5z

FTP reply codes:

Code	Description
110	Restart marker reply.
120	Service ready in nnn minutes.
125	Data connection already open; transfer starting.
150	File status okay; about to open data connection.
200	Command okay.
202	Command not implemented, superfluous at this site.
211	(System status, or system help reply.)
212	(Directory status reply.)
213	(File status reply.)
214	(Help message.)
215	NAME system type.
220	Service ready for new user.
221	Service closing control connection.
225	Data connection open; no transfer in progress.
226	Closing data connection.
227	Entering Passive Mode <h1,h2,h3,h4,p1,p2>.
228	Entering Long Passive Mode.
229	Extended Passive Mode Entered.
230	User logged in, proceed.
250	Requested file action okay, completed.
257	"PATHNAME" created.
331	User name okay, need password.
332	Need account for login.
350	Requested file action pending further information.
421	Service not available, closing control connection.
425	Can't open data connection.
426	Connection closed; transfer aborted.
450	Requested file action not taken.
451	Requested action aborted. Local error in processing.
452	Requested action not taken. File unavailable (file busy)
500	Syntax error, command unrecognized.
501	Syntax error in parameters or arguments.
502	Command not implemented.
503	Bad sequence of commands.
504	Command not implemented for that parameter.
521	Supported address families are <af1, .., afn>
522	Protocol not supported.
530	Not logged in.
532	Need account for storing files.
550	Requested action not taken. File unavailable (not found, no access).
551	Requested action aborted. Page type unknown.
552	Requested file action aborted.
553	Requested action not taken. File name not allowed.
554	Requested action not taken: invalid REST parameter.
555	Requested action not taken: type or stru mismatch.

LIST information in UNIX-style format:

In following format every entry will send to the client using the UNIX List format.

attribs

links

owner

group

size

date & time/year

name

CR/LF

	spacer (0x20)	1 byte
attribs	attributes of this entry (type/owner/group/anyone)	10 bytes
links	link counter (right justified)	3..5 bytes
owner	owner name (left justified)	8..10 bytes
group	group name (left justified)	8..10 bytes
size	size of this entry (right justified)	7..10 bytes
date & time/year	creation/last-change date & time/year (left justified)	12 bytes
name	name of this entry (no filling)	1..255 bytes
CR/LF	end-of-line (0x0D & 0x0A)	2 byte

attributes :

type	owner	group	anyone
-	r w x	r w x	r w x

• type (first character)

-	the entry is a ordinary file
b	the entry is a block special file
c	the entry is a character special file
d	the entry is a directory
l	the entry is a symbolic link
p	the entry is a FiFo special file (pipe)
s	the entry is a local socket

• owner / group / anyone (a 3 bytes)

r	read
w	write (edit)
x	execute (search)
-	corresponding permission not granted

link counter :

The number of links to this entry. The size of this field is 3..5 characters with blanks plus right justified value, like " 1".

owner name :

The name of the owner of this entry. This is the user profile name of the entry-owner. The size of this field is 8..10 characters with the left justified name-string plus filling blanks, like "ftp ".

group name :

The name of the group of this entry. This is the group profile name of the entry. The size of this field is 8..10 characters with the left justified name-string plus filling blanks, like "service ".

size :

The size of this entry in bytes. The size of this field itself is 7..10 characters with blanks plus right justified value in decimal characters, like " 1024". Directories alltimes have a size of 0.

date & time/year :

The modification time of this entry. The size of this field is fix 12 characters with left justified value in following format.

• last modification in the previous 180 days

"Mmm dd hh:mm"

• last modification not in the previous 180 days

"Mmm dd yyyy"

with the following description of the elements:

Mmm	abbreviated month ("Jan", Feb", ..)
dd	day of the month, right justified and padded with blank (" 1" .. "31")
hh	hour, right justified and padded with ZERO ("00" .. "23")
mm	minute, right justified and padded with ZERO ("00" .. "59")
yyyy	year, right justified but alltimes 4 characters ("1980" ..)

name :

The name of this entry. This field have a vaiable length, depends on the name of this entry and can includes blanks. After this field the line (this entry) will closed (without a spacer) with a CR+LF.

example:

"drwxr--r-- 1 ftp service 0 Jul 8 2005 images"
"-rw-r--r-- 1 ftp service 2038 Aug 16 09:23 index.html"

V4