[ 本帖最后由 luluboy 于 2010-12-22 00:27 编辑 ]作者: 钉子 时间: 2010-12-21 17:09
当然是SMTP，具体原理，就要看SMTP的标准文档了。作者: tdk 时间: 2010-12-21 23:30
RCPT TO:User@Site.Domain.Com notify=success,failure作者: tdk 时间: 2010-12-21 23:31
就是这个命令作者: luluboy 时间: 2010-12-22 00:26
恩 感谢啦。。。
找到IETF的描述了。。。这回我知道，是哪里发出这份是否成功发送至服务器的回复了。
RFC 3461 SMTP DSN Extension http://datatracker.ietf.org/doc/rfc3461/?include_text=1
Simple Mail Transfer Protocol (SMTP) Service Extension
for Delivery Status Notifications (DSNs)
截了一段，希望对大家有用：
^_^
3. The Delivery Status Notification service extension
An SMTP client wishing to request a DSN for a message may issue the
EHLO command to start an SMTP session, to determine if the server
supports any of several service extensions. If the server responds
with code 250 to the EHLO command, and the response includes the EHLO
keyword DSN, then the Delivery Status Notification extension (as
described in this memo) is supported.
Ordinarily, when an SMTP server returns a positive (2xx) reply code
in response to a RCPT command, it agrees to accept responsibility for
either delivering the message to the named recipient, or sending a
notification to the sender of the message indicating that delivery
has failed. However, an extended SMTP ("ESMTP") server which
implements this service extension will accept an optional NOTIFY
parameter with the RCPT command. If present, the NOTIFY parameter
alters the conditions for generation of Delivery Status Notifications
from the default (issue notifications only on failure) specified in
[1]. The ESMTP client may also request (via the RET parameter)
whether the entire contents of the original message should be
returned (as opposed to just the headers of that message), along with
the DSN.
In general, an ESMTP server which implements this service extension
will propagate Delivery Status Notification requests when relaying
mail to other SMTP-based MTAs which also support this extension, and
make a "best effort" to ensure that such requests are honored when
messages are passed into other environments.
In order for Delivery Status Notifications to be meaningful to the
sender, ESMTP servers, which support this extension, should propagate
the following information for use in generating DSNs to any other
MTAs that are used to relay the message:
(a) for each recipient, a copy of the original recipient address, as
used by the sender of the message.
This address need not be the same as the mailbox specified in
the RCPT command. For example, if a message was originally
addressed to A@B.C and later forwarded to A@D.E, after such
forwarding has taken place, the RCPT command will specify a
mailbox of A@D.E. However, the original recipient address
remains A@B.C.
Also, if the message originated from an environment which does
not use Internet-style user@domain addresses, and was gatewayed
into SMTP, the original recipient address will preserve the
original form of the recipient address.
(b) for the entire SMTP transaction, an envelope identification
string, which may be used by the sender to associate any
delivery status notifications with the transaction used to send
the original message.