|
SMTP protocol specific response code design provides some useful (numeric) codes used for reporting mail (delivery status) system errors (Protocol–a method of sending and receiving data). SMTP is a simple ASCII protocol. SMTP is a protocol governing electronic mail transmission and reception (sending and receiving emails between mail servers). Operational Sequent
of: How two MTAs (Message Transfer Agent) communicate with each other using a single TCP connection.
*If not--There are no standard mechanism for reporting mail system errors except for the limited codes consisting of three numbers offered by SMTP with specific text descriptions sent in mail messages. Because of its limitations, the majority of each code delivery report may indicate several other error conditions as well as different mail server using their own text description. The first number generally tells whether the server accepted the command and if it could manage it. 2 The server has completed the task successfully. 3 The server has
understood the request, 4 The server has
encountered a temporary failure. 5 The server has encountered an error. The second number gives more
information. 0 A syntax error has
occurred. The third number shows more graduations of the mail transfer status to return a more detailed report as detailed in the ESMTP server response codes defined in RFC 821 and later extensions. Example of an older SMTP response text
description for the first number. 4.x.x Persistent Transient Failure 5.x.x Permanent Failure
(The
server has encountered an
error).
Example of
a new ESMTP response 501 5.5.4 Syntax error 501 Syntax error represent the enhanced SMTP (ESMTP) status code 5.5.4 represent the old SMTP status code
|
|
