FTP 215 System Type vs 551 Page Type Unknown
FTP 215 (System Type) is a 2xx Positive Completion response, while 551 (Page Type Unknown) is a 5xx Permanent Negative response. 215 indicates that the NAME system type, where NAME is an official system name from the list in the Assigned Numbers document. Reports the operating system of the server. In contrast, 551 means that requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
描述
The NAME system type, where NAME is an official system name from the list in the Assigned Numbers document. Reports the operating system of the server.
何时出现
After issuing the SYST command. The server reports its operating system type, commonly 'UNIX Type: L8' or 'Windows_NT'.
如何修复
No fix needed — use this information to adjust path separators and line endings for the server's OS type.
描述
Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
何时出现
When attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
如何修复
Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.
主要区别
215 is a 2xx Positive Completion response, while 551 is a 5xx Permanent Negative response.
FTP 215: The NAME system type, where NAME is an official system name from the list in the Assigned Numbers document. Reports the operating system of the server.
FTP 551: Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
You encounter 215 when after issuing the SYST command. The server reports its operating system type, commonly 'UNIX Type: L8' or 'Windows_NT'.
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.
何时使用哪个
For 215 (System Type): No fix needed — use this information to adjust path separators and line endings for the server's OS type. 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.