FTP 202 Command Superfluous vs 425 Can't Open Data Connection
FTP 202 (Command Superfluous) is a 2xx Positive Completion response, while 425 (Can't Open Data Connection) is a 4xx Transient Negative response. 202 indicates that the command is not implemented but is recognized as superfluous. The server acknowledges the command but it has no effect. In contrast, 425 means that can't open data connection. The server was unable to establish the data channel needed for the file transfer.
คำอธิบาย
The command is not implemented but is recognized as superfluous. The server acknowledges the command but it has no effect.
เมื่อคุณพบเห็น
When you send a command the server recognizes but considers unnecessary, such as ALLO on a server that does not require pre-allocation.
วิธีแก้ไข
No fix needed — the server is telling you the command is not necessary. You can safely ignore this response and continue.
คำอธิบาย
Can't open data connection. The server was unable to establish the data channel needed for the file transfer.
เมื่อคุณพบเห็น
When a firewall or NAT is blocking the data connection, or the client failed to connect to the server's passive port.
วิธีแก้ไข
Switch between active (PORT) and passive (PASV) modes. Check that your firewall allows the FTP data port range and that NAT is configured correctly.
ความแตกต่างหลัก
202 is a 2xx Positive Completion response, while 425 is a 4xx Transient Negative response.
FTP 202: The command is not implemented but is recognized as superfluous. The server acknowledges the command but it has no effect.
FTP 425: Can't open data connection. The server was unable to establish the data channel needed for the file transfer.
You encounter 202 when when you send a command the server recognizes but considers unnecessary, such as ALLO on a server that does not require pre-allocation.
You encounter 425 when when a firewall or NAT is blocking the data connection, or the client failed to connect to the server's passive port.
ควรใช้อันไหนเมื่อไร
For 202 (Command Superfluous): No fix needed — the server is telling you the command is not necessary. You can safely ignore this response and continue. For 425 (Can't Open Data Connection): Switch between active (PORT) and passive (PASV) modes. Check that your firewall allows the FTP data port range and that NAT is configured correctly.