Question
SMTP stands for “Simple Mail Transport Protocol”
SMTP is the name of the protocol that is used to transfer email messages between computers. This “language” has only ten or so words and some additional enhancements (called Enhanced SMTP or ESMTP) to reduce bandwidth and improve performance.
Answer
Below are ESMTP commands supported by GMS Mail:
8BitMIME:
The sender uses this command to announce that is supports higher bit ASCII transmission.
AUTH:
Use ‘Auth’ to set up authenticated SMTP transactions. GMS Mail supports three types of authentication.
(LOGON, MD5, CRAM-MD5)
DSN:
This option asks the Gordano mail server to confirm that a transaction was completed as desired.
You could you use DSN to act as a receipt mail message to confirm when the intended receiver has received your message.
ENHANCED STATUS CODES:
This gives precise error codes relating to the status of delivering mail. These are only delivered to servers who issue the EHLO command to indicate that they understand ESMTP, all other servers receive the standard responses codes.
Example:
If mail failed to send, using standard SMTP the server might issue a ‘550 delivery failure’ whilst using enhanced SMTP the server might return 550 5.4.3 delivery failure. The extra numbers indicating that this was definitely because of a routing server failure.
ETRN:
This command is also known as QSND. It is specifically designed to allow intergration with dial-up mail servers. A dial-up mail server can connect to GMS Mail and issue the ETRN command to basically force all the e-mail for its server to be posted out.
Note: The standard ETRN specified in RFC 821 is not secure! Anyone issuing ETRN for a domain can retrieve mail for that domain. GMS Mail can be password secured.
PIPELINING:
A sending server can use pipelining to send all messages to the receiving, at once using one connection without having to use the RSET command each time.
RESTART:
Also known as Checkpoint. If a connection is dropped half way through a mail message, on its reconnection the Restart command from the sender gives receiver the option of continuing.
SIZE:
This can set restriction on the total size of messages accepted for a particular domain. The sending server will state it has a message size constraint to the receiving sender. This will then either be accepted or not.
VRFY:
This command will actually verify a user. This enables external servers to check that an e-mail account actually exists on your server. The response will be the user specified with the domain name.
XTND:
This command supports two elements; XMIT and XLIST
XMIT:
This is used to send mail via POP servers rather than SMTP.
XLIST:
This is used to list message headers.
See Also:
- Why do I see SIZE errors in the SMTP log?
- Why can’t my remote users authenticate using ESMTP AUTH?
- What is contained in release 3075?
Keywords:SMTP ESMTP Enhanced Benefits