Name
DeliverByMin
Synopsis
RFC2852 defines a way to ensure that a message is delivered or bounced within a defined maximum window of time. This method is known as the DELIVERBY SMTP extension and is used like the following (shown in bold):
220 your.host.domain ESMTP Sendmail 8.12.7/8.12.7; Fri, 13 Dec 2002 10:09:06 -0600 (MDT) EHLO another.host.domain 250-your.host.domain Hello another.host.domain [123.45.67.8], pleased to meet you 250-ENHANCEDSTATUSCODES 250-PIPELINING 250-8BITMIME 250-SIZE 250-DSN 250-ETRN250-DELIVERBY
← note 250 HELP MAIL From:<bob@another.host.domain>BY=600;R
← note 250 2.1.0 <bob@another.host.domain>... Sender ok
Here, your site tells the connecting site that it supports the
DELIVERBY SMTP extension by displaying the
250-DELIVERBY
line. Then the other site recognizes
that support and says that it wants the message delivered within 600
seconds by including the BY=600;R
as part of the
envelope sender MAIL FROM: command.
The ;R
tells your server to not relay this message
to a site that does not support this extension. The only possibility,
other than ;R
, is a ;N
, which
means the message can be relayed to another site, regardless of
whether that other site supports this extension.
It is possible to run software or a configuration at your site in such a way that mail cannot be immediately delivered. If you screen all messages for viruses, for example, or if you queue all inbound mail and deliver from the queue, you will likely not be able to guarantee immediate ...
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