List of FTP server return codes

FTP server return codes always have three digits, and each digit has a special meaning.[1] The first digit denotes whether the response is good, bad or incomplete:

Range Purpose
1xx Positive Preliminary reply

The requested action is being initiated; expect another reply before proceeding with a new command. (The user-process sending another command before the completion reply would be in violation of protocol; but server-FTP processes should queue any commands that arrive while a preceding command is in progress.) This type of reply can be used to indicate that the command was accepted and the user-process may now pay attention to the data connections, for implementations where simultaneous monitoring is difficult. The server-FTP process may send at most, one 1xx reply per command.

2xx Positive Completion reply

The requested action has been successfully completed. A new request may be initiated.

3xx Positive Intermediate reply

The command has been accepted, but the requested action is being held in abeyance, pending receipt of further information. The user should send another command specifying this information. This reply is used in command sequence groups.

4xx Transient Negative Completion reply

The command was not accepted and the requested action did not take place, but the error condition is temporary and the action may be requested again. The user should return to the beginning of the command sequence, if any. It is difficult to assign a meaning to "transient", particularly when two distinct sites (Server- and User-processes) have to agree on the interpretation. Each reply in the 4xx category might have a slightly different time value, but the intent is that the user-process is encouraged to try again. A rule of thumb in determining if a reply fits into the 4xx or the 5xx (Permanent Negative) category is that replies are 4xx if the commands can be repeated without any change in command form or in properties of the User or Server (e.g., the command is spelled the same with the same arguments used; the user does not change his file access or user name; the server does not put up a new implementation.)

5xx Permanent Negative Completion reply

The command was not accepted and the requested action did not take place. The User-process is discouraged from repeating the exact request (in the same sequence). Even some "permanent" error conditions can be corrected, so the human user may want to direct his User-process to reinitiate the command sequence by direct action at some point in the future (e.g., after the spelling has been changed, or the user has altered his directory status.)

6xx Protected reply

The RFC 2228 introduced the concept of protected replies to increase security over the FTP communications. The 6xx replies are Base64 encoded protected messages that serves as responses to secure commands. When properly decoded, these replies fall into the above categories.

The second digit is a grouping digit and encodes the following information:

Range Purpose
x0x Syntax

These replies refer to syntax errors, syntactically correct commands that don't fit any functional category, unimplemented or superfluous commands.

x1x Information

These are replies to requests for information, such as status or help.

x2x Connections

Replies referring to the control and data connections.

x3x Authentication and accounting

Replies for the login process and accounting procedures.

x4x Unspecified as of RFC 959.
x5x File system

These replies indicate the status of the Server file system vis-a-vis the requested transfer or other file system action.

Below is a list of all known return codes that may be issued by an FTP server.

Code Explanation
100 Series The requested action is being initiated, expect another reply before proceeding with a new command.
110 Restart marker replay . In this case, the text is exact and not left to the particular implementation; it must read: MARK yyyy = mmmm where yyyy is User-process data stream marker, and mmmm server's equivalent marker (note the spaces between markers and "=").
120 Service ready in nnn minutes.
125 Data connection already open; transfer starting.
150 File status okay; about to open data connection.
200 Series The requested action has been successfully completed.
202 Command not implemented, superfluous at this site.
211 System status, or system help reply.
212 Directory status.
213 File status.
214 Help message. Explains how to use the server or the meaning of a particular non-standard command. This reply is useful only to the human user.
215 NAME system type. Where NAME is an official system name from the registry kept by IANA.
220 Service ready for new user.
221 Service closing control connection.
225 Data connection open; no transfer in progress.
226 Closing data connection. Requested file action successful (for example, file transfer or file abort).
227 Entering Passive Mode (h1,h2,h3,h4,p1,p2).
228 Entering Long Passive Mode (long address, port).
229 Entering Extended Passive Mode (|||port|).
230 User logged in, proceed. Logged out if appropriate.
231 User logged out; service terminated.
232 Logout command noted, will complete when transfer done.
234 Specifies that the server accepts the authentication mechanism specified by the client, and the exchange of security data is complete. A higher level nonstandard code created by Microsoft.
250 Requested file action okay, completed.
257 "PATHNAME" created.
300 Series The command has been accepted, but the requested action is on hold, pending receipt of further information.
331 User name okay, need password.
332 Need account for login.
350 Requested file action pending further information
400 Series The command was not accepted and the requested action did not take place, but the error condition is temporary and the action may be requested again.
421 Service not available, closing control connection. This may be a reply to any command if the service knows it must shut down.
425 Can't open data connection.
426 Connection closed; transfer aborted.
430 Invalid username or password
434 Requested host unavailable.
450 Requested file action not taken.
451 Requested action aborted. Local error in processing.
452 Requested action not taken. Insufficient storage space in system. File unavailable (e.g., file busy).
500 Series Syntax error, command unrecognized and the requested action did not take place. This may include errors such as command line too long.
501 Syntax error in parameters or arguments.
502 Command not implemented.
503 Bad sequence of commands.
504 Command not implemented for that parameter.
530 Not logged in.
532 Need account for storing files.
534 Could Not Connect to Server - Policy Requires SSL
550 Requested action not taken. File unavailable (e.g., file not found, no access).
551 Requested action aborted. Page type unknown.
552 Requested file action aborted. Exceeded storage allocation (for current directory or dataset).
553 Requested action not taken. File name not allowed.
600 Series Replies regarding confidentiality and integrity
631 Integrity protected reply.
632 Confidentiality and integrity protected reply.
633 Confidentiality protected reply.
10000 Series Common Winsock Error Codes[2] (These are not FTP return codes)
10054 Connection reset by peer. The connection was forcibly closed by the remote host.
10060 Cannot connect to remote server.
10061 Cannot connect to remote server. The connection is actively refused by the server.
10066 Directory not empty.
10068 Too many users, server is full.

See also

References
  1. RFC 959
  2. Windows Socket Error Codes, Microsoft Windows Dev Center
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