FTP 110 Restart Marker Reply vs 551 Page Type Unknown
FTP 110 (Restart Marker Reply) is a 1xx Positive Preliminary response, while 551 (Page Type Unknown) is a 5xx Permanent Negative response. 110 indicates that the server is sending a restart marker reply. The text is exact and not left to interpretation. This marker is used to indicate the point at which a file transfer should be restarted. In contrast, 551 means that requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
คำอธิบาย
The server is sending a restart marker reply. The text is exact and not left to interpretation. This marker is used to indicate the point at which a file transfer should be restarted.
เมื่อคุณพบเห็น
During a resumed file transfer when the server confirms the restart position in the data stream.
วิธีแก้ไข
No fix needed — this is a normal response during transfer recovery. If restarts keep failing, verify the marker format matches what your client expects.
คำอธิบาย
Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
เมื่อคุณพบเห็น
When attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
วิธีแก้ไข
Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.
ความแตกต่างหลัก
110 is a 1xx Positive Preliminary response, while 551 is a 5xx Permanent Negative response.
FTP 110: The server is sending a restart marker reply. The text is exact and not left to interpretation. This marker is used to indicate the point at which a file transfer should be restarted.
FTP 551: Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
You encounter 110 when during a resumed file transfer when the server confirms the restart position in the data stream.
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.
ควรใช้อันไหนเมื่อไร
For 110 (Restart Marker Reply): No fix needed — this is a normal response during transfer recovery. If restarts keep failing, verify the marker format matches what your client expects. 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.