SMTP 211 System Status vs 252 Cannot Verify User
Both SMTP 211 (System Status) and 252 (Cannot Verify User) belong to the 2xx Positive Completion category. 211 indicates that a system status reply providing information about the mail server's current state. This is typically sent in response to a HELP or system inquiry command. Meanwhile, 252 means that the server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information.
描述
A system status reply providing information about the mail server's current state. This is typically sent in response to a HELP or system inquiry command.
何时出现
When querying the mail server for its status or capabilities. The server is sharing diagnostic or informational details about itself.
如何修复
No fix needed — this is an informational response. If the status indicates a problem, review the server's configuration or contact the mail administrator.
描述
The server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information.
何时出现
When using the VRFY command to check if a recipient exists. The server refuses to confirm or deny the address, typically as a spam-prevention measure.
如何修复
No fix needed — the server will still attempt delivery. If you need to verify addresses, contact the mail administrator or rely on bounce-back messages instead.
主要区别
SMTP 211: A system status reply providing information about the mail server's current state. This is typically sent in response to a HELP or system inquiry command.
SMTP 252: The server cannot verify the user but will accept the message and attempt delivery. This is often returned in response to VRFY when the server intentionally hides user information.
You encounter 211 when when querying the mail server for its status or capabilities. The server is sharing diagnostic or informational details about itself.
You encounter 252 when when using the VRFY command to check if a recipient exists. The server refuses to confirm or deny the address, typically as a spam-prevention measure.
何时使用哪个
For 211 (System Status): No fix needed — this is an informational response. If the status indicates a problem, review the server's configuration or contact the mail administrator. For 252 (Cannot Verify User): No fix needed — the server will still attempt delivery. If you need to verify addresses, contact the mail administrator or rely on bounce-back messages instead.