On 08 Apr 2003 12:13:00 +0200
list-ietf-antispam <list-ietf-antispam(_at_)faerber(_dot_)muc(_dot_)de> wrote:
Vernon Schryver <vjs(_at_)calcite(_dot_)rhyolite(_dot_)com> schrieb/wrote:
Well, you have to err on the safe side: As a client, unless you have
positivly seen the "250 OK", you have to resend. As a server, you have
to deliver the message if you sent the "250 OK". So lost messages
should not occur (although they reportedly do due to broken servers).
It is impossible to get two nodes to have perfect knowledge that they
share the same data at the same instant over a non-instantaneous link.
In the case of SMTP this is realised by the server sending the 250 and
the client never receiving it (due to crash, lost connection, routing
error, whatever). The server thinks it got the message and everything
is fine. The client never got the ack, and so retries the delivery
later. This is nothing to do with broken servers.
That said, a more common cause is broken servers mishandling of
rejections mid a RCPT-TO packet.
--
J C Lawrence
---------(*) Satan, oscillate my metallic sonatas.
claw(_at_)kanga(_dot_)nu He lived as a devil, eh?
http://www.kanga.nu/~claw/ Evil is a name of a foeman, as I live.
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