FTP 110 Restart Marker Reply vs 125 Data Connection Open
Both FTP 110 (Restart Marker Reply) and 125 (Data Connection Open) belong to the 1xx Positive Preliminary category. 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. Meanwhile, 125 means that the data connection is already open and the transfer is beginning. No need to open a new data connection.
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
The data connection is already open and the transfer is beginning. No need to open a new data connection.
When You See It
When the server reuses an existing data connection for a file transfer instead of opening a new one.
How to Fix
No fix needed — the transfer is starting immediately. Your client should begin reading or writing data on the existing connection.
Key Differences
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 125: The data connection is already open and the transfer is beginning. No need to open a new data connection.
You encounter 110 when during a resumed file transfer when the server confirms the restart position in the data stream.
You encounter 125 when when the server reuses an existing data connection for a file transfer instead of opening a new one.
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 125 (Data Connection Open): No fix needed — the transfer is starting immediately. Your client should begin reading or writing data on the existing connection.