Ftp 503 ошибка

Errors can be frustrating, especially if they are cryptic, like this:

Response: 150 opening data connection
Response: 503 Failure of data connection.

You know that the connection has failed (obviously!), but where?

Here at Bobcares.com, we help Web hosts, VPS users and website users troubleshoot such errors as part of our Outsourced Hosting Support services.

503 failure of data connection is a common error seen in FileZilla FTP client.

What is “503 failure of data connection”?

This error says that the FTP client was unable to contact the server’s FTP port, which means that the connection was blocked somewhere along the way.

It could be in the user’s PC, the modem, within the office network, ISP, or the server.

Here are the top 5 causes we’ve seen for this error, and how we fix them.

1. FTP client set to Active mode

FTP transfers can happen in Active or Passive mode.

To use Active FTP, users must configure their PCs to allow incoming connections FROM the server to a non-standard port (Port 21 is the standard FTP port. Port 30231 is a non-standard one).

Such an incoming connection closely resembles a cyber attack, and most firewalls block such non-standard connections.

We’ve seen cases where FTP users accidentally set their FTP mode to Active, causing the connection to fail.

To solve this, we help the users navigate the settings and choose Passive mode. We recommend this to be set by default for all FTP accounts.

2. Unsupported FTP features (eg. SFTP, SSL, etc.)

Some hosts offer SFTP or FTP over SSH. It uses port 22 instead of the traditional FTP port 21.

Similarly, some hosts offer FTP over SSL that uses port 990.

We’ve seen users mixing up these two, or even trying to establish a SSL/TLS connection where no such facility exists.

When users attempt to connect to an unsupported port, the server firewall will block that connection, and it’ll result in the error 503 failure of data connection.

To fix this we recommend customers to use the basic FTP protocol. To set it in FileZilla, go to  File > Site Manager > Encryption > Only use plain FTP(insecure).

3. Blocked by firewall or antivirus software

The FileZilla error 503 failure of data connection goes on to state:

“This means that some router and/or firewall is still interfering with Filezilla.”

So, many users try to turn off their PC firewall, but still face issues.

We’ve seen that this is sometimes caused by Antivirus and Antispyware tools that acts as a second layer of firewall.

We resolve this by asking the users to turn of all security applications one by one. This helps us figure out exactly which app is causing the error, and fix its settings.

4. Blocked by intermediate routers or gateway devices

FTP users are sometimes unaware of firewalls that exist outside their PC.

This is especially true in large offices where people sit behind a local network (LAN).

We’ve seen routers, gateways or proxies that block outbound connections through port 22 (SFTP) or 990 (FTP over TLS).

To resolve this, we ask customers to turn off their gateways or routers, and establish a direct connection to the net. This helps us isolate where the block is happening.

Once we’ve confirmed that the issue is indeed with the intermediate devices, the users can work with their IT team to fix the device.

5. Port range not open at the server

The proper functioning of FTP requires that the server accept connections in all standard ports (eg. 21, 20, 22 and 990).

In addition, it also should accept connections on passive FTP ports, which varies from one server to another.

The trouble is, server firewalls allow only connections to the standard ports by default. If it’s not specifically set to allow connections to Passive FTP ports, the connections will fail.

We’ve seen newly setup VPS servers blocking Passive FTP ports.

Similarly, we’ve seen FTP ports of newly setup FTP servers in Windows IIS blocked as well in firewall.

To fix this, we add firewall exclusion rules:

• Linux IPtables – Add the rule iptables -A INPUT -p tcp --match multiport --dports XXXXX:ZZZZZ -j ACCEPT where XXXXX is the starting port, and ZZZZZ is the ending port in the Passive port range.
• Windows IIS –  Go to Control Panel > System and Security > Windows Firewall > Advanced Settings > Inbound Rules > FTP server rules > Actions > Enable Rule.

Conclusion

503 failure of data connection is a common FTP error caused when the FTP connection to the server is blocked by some device or software between the PC and the server. Today we’ve seen the top 5 causes for this error, and how we fix them.

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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

RFC 2228 introduced the concept of protected replies to increase security over 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.

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. Logged out if appropriate. 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. 232 User logged in, authorized by security data exchange. 234 Server accepts the security mechanism specified by the client; no security data needs to be exchanged. 235 Server accepts the security data given by the client; no further security data needs to be exchanged. 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. 334 Server accepts the security mechanism specified by the client; some security data needs to be exchanged. 335 Server accepts the security data given by the client; more security data needs to be exchanged. 336 Username okay, need password. Challenge is «….». 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 431 Need some unavailable resource to process security. 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. 533 Command protection level denied for policy reasons. 534 Request denied for policy reasons. 535 Failed security check. 536 Data protection level not supported by security mechanism. 537 Command protection level not supported by security mechanism. 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. 10065 No route to host / DNS cannot be resolved. 10066 Directory not empty. 10068 Too many users, server is full.

Yesterday while trying to access my web hosting account, I received an error message «503 Login Authentication Failed«. I have been using FireFTP as my FTP client for one year and I never faced such an issue. I had been using FileZilla before migrating to FireFTP but it never showed such a problem. However, I do not believe it is an issue with FireFTP. I have checked the username, password and host address once again but they are correct. I tried to log in to web host account a few more times but received the same error. One time it showed a different alert with the same code. The new popup was «503 Login error«. This tutorial explains the reasons and solution of «503 Login Authentication Failed«. Since I was in a hurry, I couldn’t troubleshoot the issue by myself. I deleted the entire FTP cache and entered the FTP server access details manually once again. This time I didn’t face any trouble to access the web server. I have saved the screenshot of the popup I received.

Today morning I started searching for more about this message. In many discussion forums, experts say «503 Login Authentication Failed» is due to the incorrect username or password. You may get the alert if the host address is typed wrongly. Another possibility is the usage of Caps Lock without knowing that key is on while entering username and password. Anyway, after clearing the cache of my FTP program (deleted previously saved username, password and host address), I successfully logged in to my server ftp account.

Solution For FTP Error 503 Login Authentication Failed

The reason for 503 Login Authentication Failed: An FTP error occurred — cannot make connection to host is the incorrect File Transfer Protocol login information.

• Port Number should be 21 (FTP server use port number 21 to transfer files).
• Host address, FTP username, and password should be correct
• Make sure Caps Lock is turned off
• If still the problem is not fixed, clear the cache

PS: Clearing cache means delete all stored FireFTP usernames, passwords, and host addresses. This procedure cannot be undone, so make sure you have the backup of the necessary details you entered.

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Technology Blog

LIST OF COMMON FTP ERROR CODES

File Transfer Protocol (FTP) is a network protocol responsible for transferring file between hosts. An FTP on the other hand, is a server that serves as a central reposi tory for files that users can download and, in some cases, upload.

It can then also authenticate users based on user name and password combination but and FTP server can also be configured to allow users to connect anonymously.

FTP uses TCP/IP port 20 and 21; port 20 is for transmitting data between the FTP server and client while the port 21 is used for transmitting instructions between the FTP server and client.

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

NOTE: Error messages are very much important to be read whenever they appear on our computer screen or any electronic device. It really helps us to understand the situation at hand.  Below are brief explanations of the most common status and error codes. The table below is provided so that you have some idea whether you can solve the issue on your own or you need to call your ISP for assistance.

ERROR CODES	MEANINGS
230	User logged in, proceed. Logged out if appropriate.
227	Entering Passive Mode (h1, h2, h3, h4, p1, p2).
250	Requested file action okay, completed.
257	“PATHNAME” created
120	Service ready in nnn minutes.
125	Data connection already open; transfer starting
350	Requested file action pending further information
331	User name okay, need password.
332	Need account for login.
213	File status.
425	Can’t open data connection
212	Directory status.
150	File status okay; about to open data connection.
200	Command okay.
202	Command not implemented, superfluous at this site.
530	Not logged in
501	Syntax error in parameters or arguments.
220	Service ready for new user.
503	Bad sequence of commands.
211	System status, or system help reply.
421	Service not available, closing control connection. This may be a reply to any command if the service knows it must shut down.
214	Help message. On 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 list in the Assigned Numbers document.
532	Need account for storing files.
502	Command not implemented.
504	Command not implemented for that parameter.
550	Requested action not taken. File unavailable (e.g., file not found, no access).
225	Data connection open; no transfer in progress.
426	Connection closed; transfer aborted.
226	Closing data connection. Requested file action successful (for example, file transfer or file abort).
552	Requested file action aborted. Exceeded storage allocation (for current directory or dataset).
551	Requested action aborted. Page type unknown.
221	Service closing control connection.
553	Requested action not
450	Requested file action not taken
451	Requested action aborted. Local error in processing.
500	Syntax error, command unrecognized. This may include errors such as command line too long.
452	Requested action not taken. Insufficient storage space in system. File unavailable (e.g., file busy).

So all of a sudden certain users when trying to FTP get the 503 error.

Here is the full error when I try logging in as a user:

Response: 530-User cannot log in, home directory inaccessible.

Response: Win32 error: Access is denied.

Response: Error details: File system denied the access.

Response: 530 End

Error: Critical error: Could not connect to server

The really odd thing is some users can login and others no, all settings the same and this has been working for years.

Windows server 2008 r2

I have setup user isolation settings and like I said there have been no issues up till yesterday where a handful of users can’t login.

Any help would be great, i have looked at all related posts here and nothing has worked.

Anonymous authentication was turned on and off, didn’t change.

Reset all accounts and nothing, delete accounts and created new ones linked to the new virtual dir and still can’t login.

Thanks!