FTP 150 File Status OK vs 551 Page Type Unknown
FTP 150 (File Status OK) is a 1xx Positive Preliminary response, while 551 (Page Type Unknown) is a 5xx Permanent Negative response. 150 indicates that the file status is okay and the server is about to open the data connection for the transfer. This is the normal precursor to a file transfer. In contrast, 551 means that requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
Descripción
The file status is okay and the server is about to open the data connection for the transfer. This is the normal precursor to a file transfer.
Cuándo lo verás
Right before a file download or upload begins, confirming the file is accessible and the data channel is being opened.
Cómo solucionarlo
No fix needed — this means the transfer is about to start. If the transfer stalls after this reply, check firewall rules blocking the data connection.
Descripción
Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
Cuándo lo verás
When attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
Cómo solucionarlo
Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.
Diferencias clave
150 is a 1xx Positive Preliminary response, while 551 is a 5xx Permanent Negative response.
FTP 150: The file status is okay and the server is about to open the data connection for the transfer. This is the normal precursor to a file transfer.
FTP 551: Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
You encounter 150 when right before a file download or upload begins, confirming the file is accessible and the data channel is being opened.
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.
Cuándo usar cada uno
For 150 (File Status OK): No fix needed — this means the transfer is about to start. If the transfer stalls after this reply, check firewall rules blocking the data connection. 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.