FTP 110 Restart Marker Reply vs 500 Syntax Error
FTP 110 (Restart Marker Reply) is a 1xx Positive Preliminary response, while 500 (Syntax Error) 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, 500 means that syntax error, command unrecognized. The server could not parse the command. This may also be sent when the command line is too long.
Description
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.
When You See It
During a resumed file transfer when the server confirms the restart position in the data stream.
How to Fix
No fix needed — this is a normal response during transfer recovery. If restarts keep failing, verify the marker format matches what your client expects.
Description
Syntax error, command unrecognized. The server could not parse the command. This may also be sent when the command line is too long.
When You See It
When you send a malformed or misspelled command, or a command the server does not recognize at all.
How to Fix
Check the command spelling and syntax. Use HELP to see the list of supported commands on this server.
Key Differences
110 is a 1xx Positive Preliminary response, while 500 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 500: Syntax error, command unrecognized. The server could not parse the command. This may also be sent when the command line is too long.
You encounter 110 when during a resumed file transfer when the server confirms the restart position in the data stream.
You encounter 500 when when you send a malformed or misspelled command, or a command the server does not recognize at all.
When to Use Which
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 500 (Syntax Error): Check the command spelling and syntax. Use HELP to see the list of supported commands on this server.