FTP 220 Service Ready vs 450 File Action Not Taken
FTP 220 (Service Ready) is a 2xx Positive Completion response, while 450 (File Action Not Taken) is a 4xx Transient Negative response. 220 indicates that service ready for new user. This is the greeting message sent by the FTP server when a client first connects. In contrast, 450 means that requested file action not taken. The file is unavailable due to being busy, locked by another process, or temporarily inaccessible.
説明
Service ready for new user. This is the greeting message sent by the FTP server when a client first connects.
このコードが表示される場合
Immediately upon connecting to an FTP server. This is the welcome banner confirming the server is accepting connections.
解決方法
No fix needed — the server is ready. Proceed with USER and PASS commands to authenticate.
説明
Requested file action not taken. The file is unavailable due to being busy, locked by another process, or temporarily inaccessible.
このコードが表示される場合
When you try to access a file that is locked by another user or process, or when the server temporarily cannot process the file.
解決方法
Wait and retry the operation — the file may be locked by another transfer. If persistent, check server-side file locks and permissions.
主な違い
220 is a 2xx Positive Completion response, while 450 is a 4xx Transient Negative response.
FTP 220: Service ready for new user. This is the greeting message sent by the FTP server when a client first connects.
FTP 450: Requested file action not taken. The file is unavailable due to being busy, locked by another process, or temporarily inaccessible.
You encounter 220 when immediately upon connecting to an FTP server. This is the welcome banner confirming the server is accepting connections.
You encounter 450 when when you try to access a file that is locked by another user or process, or when the server temporarily cannot process the file.
どちらをいつ使うか
For 220 (Service Ready): No fix needed — the server is ready. Proceed with USER and PASS commands to authenticate. For 450 (File Action Not Taken): Wait and retry the operation — the file may be locked by another transfer. If persistent, check server-side file locks and permissions.