FTP 211 System Status vs 503 Bad Sequence
FTP 211 (System Status) is a 2xx Positive Completion response, while 503 (Bad Sequence) is a 5xx Permanent Negative response. 211 indicates that system status or system help reply. The server provides information about its current status or available features. In contrast, 503 means that bad sequence of commands. The command is valid but was sent in the wrong order relative to other commands.
描述
System status or system help reply. The server provides information about its current status or available features.
何时出现
After issuing the STAT command without arguments, the server returns its system status and supported features.
如何修复
No fix needed — this is an informational response. Use the information to understand the server's capabilities and current state.
描述
Bad sequence of commands. The command is valid but was sent in the wrong order relative to other commands.
何时出现
When you skip a required step, like sending PASS before USER, or RNTO without first sending RNFR.
如何修复
Follow the correct command sequence. Common sequences: USER then PASS for login, RNFR then RNTO for rename, PASV then RETR for transfer.
主要区别
211 is a 2xx Positive Completion response, while 503 is a 5xx Permanent Negative response.
FTP 211: System status or system help reply. The server provides information about its current status or available features.
FTP 503: Bad sequence of commands. The command is valid but was sent in the wrong order relative to other commands.
You encounter 211 when after issuing the STAT command without arguments, the server returns its system status and supported features.
You encounter 503 when when you skip a required step, like sending PASS before USER, or RNTO without first sending RNFR.
何时使用哪个
For 211 (System Status): No fix needed — this is an informational response. Use the information to understand the server's capabilities and current state. For 503 (Bad Sequence): Follow the correct command sequence. Common sequences: USER then PASS for login, RNFR then RNTO for rename, PASV then RETR for transfer.