FTP 220 Service Ready vs 331 Username OK, Need Password
FTP 220 (Service Ready) is a 2xx Positive Completion response, while 331 (Username OK, Need Password) is a 3xx Positive Intermediate 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, 331 means that user name okay, need password. The server recognized the username and is waiting for the corresponding password to complete authentication.
描述
Service ready for new user. This is the greeting message sent by the FTP server when a client first connects.
何时出现
Immediately upon connecting to an FTP server. This is the welcome banner confirming the server is accepting connections.
如何修复
No fix needed — the server is ready. Proceed with USER and PASS commands to authenticate.
描述
User name okay, need password. The server recognized the username and is waiting for the corresponding password to complete authentication.
何时出现
After sending the USER command with a valid username. The server is prompting for the PASS command.
如何修复
Send the PASS command with the correct password. If you get 530 after PASS, the password is wrong — verify your credentials.
主要区别
220 is a 2xx Positive Completion response, while 331 is a 3xx Positive Intermediate response.
FTP 220: Service ready for new user. This is the greeting message sent by the FTP server when a client first connects.
FTP 331: User name okay, need password. The server recognized the username and is waiting for the corresponding password to complete authentication.
You encounter 220 when immediately upon connecting to an FTP server. This is the welcome banner confirming the server is accepting connections.
You encounter 331 when after sending the USER command with a valid username. The server is prompting for the PASS command.
何时使用哪个
For 220 (Service Ready): No fix needed — the server is ready. Proceed with USER and PASS commands to authenticate. For 331 (Username OK, Need Password): Send the PASS command with the correct password. If you get 530 after PASS, the password is wrong — verify your credentials.