FTP 200 Command OK vs 551 Page Type Unknown
FTP 200 (Command OK) is a 2xx Positive Completion response, while 551 (Page Type Unknown) is a 5xx Permanent Negative response. 200 indicates that the command has been successfully executed. This is a general acknowledgment that the command was understood and carried out. In contrast, 551 means that requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
설명
The command has been successfully executed. This is a general acknowledgment that the command was understood and carried out.
이 코드를 보게 되는 경우
After issuing any command that completes successfully, such as TYPE, MODE, or NOOP.
해결 방법
No fix needed — the command succeeded. This is the standard positive response for commands that don't return data.
설명
Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
이 코드를 보게 되는 경우
When attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
해결 방법
Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.
주요 차이점
200 is a 2xx Positive Completion response, while 551 is a 5xx Permanent Negative response.
FTP 200: The command has been successfully executed. This is a general acknowledgment that the command was understood and carried out.
FTP 551: Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
You encounter 200 when after issuing any command that completes successfully, such as TYPE, MODE, or NOOP.
You encounter 551 when when attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
언제 어떤 것을 사용할지
For 200 (Command OK): No fix needed — the command succeeded. This is the standard positive response for commands that don't return data. For 551 (Page Type Unknown): Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.