SMTP 251 User Not Local vs 354 Start Mail Input
SMTP 251 (User Not Local) is a 2xx Positive Completion response, while 354 (Start Mail Input) is a 3xx Positive Intermediate response. 251 indicates that the recipient is not local to the server, but it will forward the message to the specified forwarding address. The server acts as a relay for this recipient. In contrast, 354 means that the server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
Описание
The recipient is not local to the server, but it will forward the message to the specified forwarding address. The server acts as a relay for this recipient.
Когда вы это видите
When sending to a recipient whose mailbox is hosted on a different server. The current server knows the forwarding address and will relay the message on your behalf.
Как исправить
No fix needed — the message will be forwarded automatically. To avoid relaying, send directly to the address provided in the server's response.
Описание
The server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
Когда вы это видите
After sending the DATA command. The server is now waiting for you to type or stream the email message, ending with a dot on its own line.
Как исправить
Send your message content followed by a line with just a period (.) to signal the end. If you get an error after this, check that your message does not contain a bare period on a line by itself within the body.
Ключевые различия
251 is a 2xx Positive Completion response, while 354 is a 3xx Positive Intermediate response.
SMTP 251: The recipient is not local to the server, but it will forward the message to the specified forwarding address. The server acts as a relay for this recipient.
SMTP 354: The server is ready to receive the message body. The client should begin sending the email content (headers and body) and terminate with a single line containing only a period (CRLF.CRLF).
You encounter 251 when when sending to a recipient whose mailbox is hosted on a different server. The current server knows the forwarding address and will relay the message on your behalf.
You encounter 354 when after sending the DATA command. The server is now waiting for you to type or stream the email message, ending with a dot on its own line.
Когда что использовать
For 251 (User Not Local): No fix needed — the message will be forwarded automatically. To avoid relaying, send directly to the address provided in the server's response. For 354 (Start Mail Input): Send your message content followed by a line with just a period (.) to signal the end. If you get an error after this, check that your message does not contain a bare period on a line by itself within the body.