FTP 215 System Type vs 503 Bad Sequence
FTP 215 (System Type) is a 2xx Positive Completion response, while 503 (Bad Sequence) is a 5xx Permanent Negative response. 215 indicates that the NAME system type, where NAME is an official system name from the list in the Assigned Numbers document. Reports the operating system of the server. In contrast, 503 means that bad sequence of commands. The command is valid but was sent in the wrong order relative to other commands.
Description
The NAME system type, where NAME is an official system name from the list in the Assigned Numbers document. Reports the operating system of the server.
When You See It
After issuing the SYST command. The server reports its operating system type, commonly 'UNIX Type: L8' or 'Windows_NT'.
How to Fix
No fix needed — use this information to adjust path separators and line endings for the server's OS type.
Description
Bad sequence of commands. The command is valid but was sent in the wrong order relative to other commands.
When You See It
When you skip a required step, like sending PASS before USER, or RNTO without first sending RNFR.
How to Fix
Follow the correct command sequence. Common sequences: USER then PASS for login, RNFR then RNTO for rename, PASV then RETR for transfer.
Key Differences
215 is a 2xx Positive Completion response, while 503 is a 5xx Permanent Negative response.
FTP 215: The NAME system type, where NAME is an official system name from the list in the Assigned Numbers document. Reports the operating system of the server.
FTP 503: Bad sequence of commands. The command is valid but was sent in the wrong order relative to other commands.
You encounter 215 when after issuing the SYST command. The server reports its operating system type, commonly 'UNIX Type: L8' or 'Windows_NT'.
You encounter 503 when when you skip a required step, like sending PASS before USER, or RNTO without first sending RNFR.
When to Use Which
For 215 (System Type): No fix needed — use this information to adjust path separators and line endings for the server's OS type. 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.