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.
説明
The command is not implemented but is recognized as superfluous. The server acknowledges the command but it has no effect.
このコードが表示される場合
When you send a command the server recognizes but considers unnecessary, such as ALLO on a server that does not require pre-allocation.
解決方法
No fix needed — the server is telling you the command is not necessary. You can safely ignore this response and continue.
説明
Can't open data connection. The server was unable to establish the data channel needed for the file transfer.
このコードが表示される場合
When a firewall or NAT is blocking the data connection, or the client failed to connect to the server's passive port.
解決方法
Switch between active (PORT) and passive (PASV) modes. Check that your firewall allows the FTP data port range and that NAT is configured correctly.
主な違い
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.
どちらをいつ使うか
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.