SMTP
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This memo defines an extension to the SMTP service whereby an SMTP
client and server may interact to give the server an opportunity to
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... Internet mail. One expected result of the use of MIME is that
SMTP will be expected to carry a much wider range of message sizes
than was previously the case. This has an impact on the amount of
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... This memo uses the mechanism defined in [5] to define extensions to
the SMTP service whereby a client ("sender-SMTP ...
... SMTP service whereby a client ("sender-SMTP") may declare the
size of a particular message to a server ("receiver-SMTP ...
... SMTP") may declare the
size of a particular message to a server ("receiver-SMTP"), after
which the server may indicate to the client that it is or is not
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... message size and
whereby a server ("receiver-SMTP") may declare the maximum message
size it is willing to accept to a client ("sender ...
... the name of the SMTP service extension is "Message Size
Declaration";
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... no additional SMTP verbs are defined by this extension.
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The remainder of this memo specifies how support for the extension
affects the behavior of an SMTP client and server.
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A client using the unextended SMTP protocol defined in [1], can only
be informed of such failures after transmitting ...
... client wishing to relay a large content may issue the EHLO
command to start an SMTP session, to determine if the server supports
any of several service ...
... CR-LF
pairs, but not the SMTP DATA command's terminating dot or doubled
quoting dots, to be transmitted by the SMTP client ...
... pairs, but not the SMTP DATA command's terminating dot or doubled
quoting dots, to be transmitted by the SMTP client after receiving
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... will always fail. The fixed maximum message size may be an
implementation artifact of the SMTP server, or it may be chosen by
the administrator of the server.
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... CR-LF sequences
between lines, but not the SMTP DATA command's terminating dot or
doubled quoting dots. Only one SIZE parameter may be specified in a
single MAIL command ...
... usually larger than the actual message size. (This has the effect of
making the counting or non-counting of SMTP DATA dots largely an
academic point.)
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... C: <open connection to server>
S: 220 sigurd.innosoft.com -- Server SMTP (PMDF V4.2-6 #1992)
C: EHLO ymir.claremont.edu
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... create
any vulnerability that has not always existed with SMTP. In addition,
no issues are addressed involving trusted systems and possible
release of information via the mechanisms described in this RFC.
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... Klensin, J., Freed, N., Rose, M., Stefferud, E., and D. Crocker, "SMTP Service Extensions", STD 11, RFC 1869(-> 2821prop), MCI, Innosoft International, Inc., Dover Beach Consulting, Inc., Network Management ...