On Sun, Apr 06, 2003 at 09:16:19AM -0600, Vernon Schryver wrote
More common examples of why relays are required and why they cannot
know whether an incoming message can be delivered during the SMTP
transaction are MX secondaries and corporate firewalls.
Is the corporate firewall a NAT machine or is it a dumb MTA that
relays to the "smart MTA" ? If it's a dumb MTA, then why is it being
used ?
How can an MX secondary or corporate firewall know not merely that
the Rcpt_To address is valid but that there will be no problems
putting the message into the mailbox? "User unknown" is not the
only 5yz SMTP error code and not the only contents of a bounce.
Then fer-cryin-out-loud, hold off on the "OK" response for a few
seconds and wait till the email is accepted. If it isn't, issue the
appropriate 5xx code after DATA:.
--
Walter Dnes <waltdnes(_at_)waltdnes(_dot_)org>
An infinite number of monkeys pounding away on keyboards will
eventually produce a report showing that Windows is more secure,
and has a lower TCO, than linux.
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