FTP server response codes are helpful for system administrators in charge of their company’s FTP server. Oftentimes, users might see these response codes listed in their favorite FTP client, such as FileZilla.
When troubleshooting a file transfer problem, it’s often helpful to identify the FTP response code that is being thrown around. It’s also important to ask what time of connection they’re using (ie FTP, SFTP or FTPS).
This guide will help you understand each element of the FTP server response code so you can get a better feel of what’s happening. It will also give you a full listing of each error code.
Shortcuts
1st Digit in the FTP Server Code 2nd Digit in the FTP Server Code 3rd Digit in the FTP Server Code Complete FTP Server Code Listing
FTP Server Response Codes: The First Digit
The first digit in the FTP server code lets you know whether or not the that step was successful. They also tell you what you should expect next. For instance, a 100 level code tells you that the process has started and to expect another code shortly.
| Range | Purpose |
|---|---|
1xx |
Positive Preliminary ReplyThe request is being initiated and you should expect another reply before proceeding with a new command. If a user sends another command before the reply completion the server-FTP process should queue the commands while this is in progress. This type of reply can 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 ReplyThe request was successful. A new request may now be sent. |
3xx |
Positive Intermediate ReplyThe command was accepted but the request is being held in abeyance, pending the receipt of more information. The user should send another command with this information. This reply is used in command sequence groups. |
4xx |
Transient Negative Completion ReplyThe command wasn’t accepted and the request didn’t occur, but the error condition is temporary and the action may be resent. The user should return to the beginning of the command sequence, if any. A rule of thumb in determining if this reply belongs to the 4xx (Temporary Negative) 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. |
5xx |
Permanent Negative Completion ReplyThe command wasn’t accepted and the requested action didn’t occur. The User-process shouldn’t repeat the exact same request (in the same sequence). Some “permanent” error conditions can be fixed, so the human user may want to direct his User-process to reinitiate the command sequence by direct action (e.g., the user has changed his directory status.) |
6xx |
Protected ReplyThe 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 decoded, these replies fall into the above categories. |
FTP Response Codes: The Second Digit
The second digit in the FTP server code lets you know what group or category the request belongs too. For instance, it tells you if it’s regarding connections or if it’s regarding authentication.
| Range | Purpose |
|---|---|
x0x |
SyntaxThese replies refer to syntax errors, syntactically correct commands that don’t fit any functional category, unimplemented or superfluous commands. |
x1x |
InformationReplies to requests for information, like help or support. |
x2x |
ConnectionsReplies regarding the control and data connections. |
x3x |
Authentication and accountingReplies for the login process and accounting procedures. |
x4x |
Unspecified as of RFC 959. |
x5x |
File systemIndicates the status of the Server file system vis-a-vis the requested transfer or other file system action. |
FTP Server Codes: The Third Digit
The third digit in the FTP serve code gives further explanation on what exactly is causing this code. Usually it’s the final piece of the puzzle.
Get our guide to a more secure and easier-to-use FTP replacement:
Get the Guide
FTP Server Codes: List of Error Codes
Here is a full list of known FTP server error codes:
| Code | Explanation |
|---|---|
100 Series |
The request has started, 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 xx minutes. |
125 |
Data connection is already open and the transfer is starting. |
150 |
File status is okay and about to open data connection. |
200 Series |
The request was successfully completed. |
202 |
Command was not implemented, superfluous at this site. |
211 |
System status, or system help reply. |
212 |
Directory status. |
213 |
File status. |
214 |
Help message. On how to use the server or the meaning of a particular non-standard command. |
215 |
NAME system type. Where NAME is an official system name from the registry kept by IANA. |
220 |
Service is ready for new user. |
221 |
Service closing control connection. |
225 |
Data connection is open and no transfer is in progress. |
226 |
Closing the 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 has logged in, proceed. Logged out if appropriate. |
231 |
User has logged out and the service is terminated. |
232 |
Logout command noted, will complete when the 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 and completed. |
257 |
“PATHNAME” created. |
300 Series |
The command was accepted, but the request 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 wasn’t accepted and the requested action didn’t occur, 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 request 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. |
550 |
Request not taken. File unavailable (e.g., file not found, no access). |
551 |
Request 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 |
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. |
Looking for an FTP Alternative? Get Our Full Guide!
Sources: SmartFile’s I.T. Personnel, Wikipedia
