SMTP 214 Help Message vs 502 Command Not Implemented
SMTP 214 (Help Message) is a 2xx Positive Completion response, while 502 (Command Not Implemented) is a 5xx Permanent Negative response. 214 indicates that a help message response containing information about the server's supported commands or a specific command's usage. This is a human-readable reply to the HELP command. In contrast, 502 means that the command is recognized by the SMTP specification but is not implemented on this server. The server understands the command but has chosen not to support it.
Mô tả
A help message response containing information about the server's supported commands or a specific command's usage. This is a human-readable reply to the HELP command.
Khi bạn thấy mã này
After sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
Cách khắc phục
No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports.
Mô tả
The command is recognized by the SMTP specification but is not implemented on this server. The server understands the command but has chosen not to support it.
Khi bạn thấy mã này
When using optional SMTP commands like VRFY, EXPN, or TURN that the server administrator has disabled, often for security or anti-spam reasons.
Cách khắc phục
Use an alternative approach — for example, if VRFY is disabled, send a test email instead of verifying the address. Check the server's EHLO response for supported extensions.
Sự khác biệt chính
214 is a 2xx Positive Completion response, while 502 is a 5xx Permanent Negative response.
SMTP 214: A help message response containing information about the server's supported commands or a specific command's usage. This is a human-readable reply to the HELP command.
SMTP 502: The command is recognized by the SMTP specification but is not implemented on this server. The server understands the command but has chosen not to support it.
You encounter 214 when after sending the HELP command to the SMTP server. The response lists available commands or provides usage details for the command you specified.
You encounter 502 when when using optional SMTP commands like VRFY, EXPN, or TURN that the server administrator has disabled, often for security or anti-spam reasons.
Khi nào dùng cái nào
For 214 (Help Message): No fix needed — this is a normal informational response. Use the provided help text to understand which commands the server supports. For 502 (Command Not Implemented): Use an alternative approach — for example, if VRFY is disabled, send a test email instead of verifying the address. Check the server's EHLO response for supported extensions.