SMTP 211 System Status vs 451 Local Error
SMTP 211 (System Status) is a 2xx Positive Completion response, while 451 (Local Error) is a 4xx Transient Negative response. 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. In contrast, 451 means that the requested action was aborted due to a local error in processing. The server encountered an internal issue that prevented it from completing the command.
คำอธิบาย
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.
เมื่อคุณพบเห็น
When querying the mail server for its status or capabilities. The server is sharing diagnostic or informational details about itself.
วิธีแก้ไข
No fix needed — this is an informational response. If the status indicates a problem, review the server's configuration or contact the mail administrator.
คำอธิบาย
The requested action was aborted due to a local error in processing. The server encountered an internal issue that prevented it from completing the command.
เมื่อคุณพบเห็น
When the receiving server hits an internal error such as a database failure, DNS lookup timeout, or anti-spam filter processing error.
วิธีแก้ไข
Retry the message later. If you control the server, check its logs for the specific error — common causes include DNS resolution failures, disk I/O errors, or database connectivity issues.
ความแตกต่างหลัก
211 is a 2xx Positive Completion response, while 451 is a 4xx Transient Negative response.
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 451: The requested action was aborted due to a local error in processing. The server encountered an internal issue that prevented it from completing the command.
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 451 when when the receiving server hits an internal error such as a database failure, DNS lookup timeout, or anti-spam filter processing error.
ควรใช้อันไหนเมื่อไร
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 451 (Local Error): Retry the message later. If you control the server, check its logs for the specific error — common causes include DNS resolution failures, disk I/O errors, or database connectivity issues.