FTP 220 Service Ready vs 501 Syntax Error in Arguments
FTP 220 (Service Ready) is a 2xx Positive Completion response, while 501 (Syntax Error in Arguments) is a 5xx Permanent 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, 501 means that syntax error in parameters or arguments. The command was recognized but its arguments are invalid or malformed.
Description
Service ready for new user. This is the greeting message sent by the FTP server when a client first connects.
When You See It
Immediately upon connecting to an FTP server. This is the welcome banner confirming the server is accepting connections.
How to Fix
No fix needed — the server is ready. Proceed with USER and PASS commands to authenticate.
Description
Syntax error in parameters or arguments. The command was recognized but its arguments are invalid or malformed.
When You See It
When you use a valid command but with wrong parameters, such as an invalid path format or incorrect argument count.
How to Fix
Review the command's required argument format. Common issues include missing quotes around paths with spaces or invalid character encoding.
Key Differences
220 is a 2xx Positive Completion response, while 501 is a 5xx Permanent 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 501: Syntax error in parameters or arguments. The command was recognized but its arguments are invalid or malformed.
You encounter 220 when immediately upon connecting to an FTP server. This is the welcome banner confirming the server is accepting connections.
You encounter 501 when when you use a valid command but with wrong parameters, such as an invalid path format or incorrect argument count.
When to Use Which
For 220 (Service Ready): No fix needed — the server is ready. Proceed with USER and PASS commands to authenticate. For 501 (Syntax Error in Arguments): Review the command's required argument format. Common issues include missing quotes around paths with spaces or invalid character encoding.