On Fri, 8 Apr 2005, Bruce Lilly wrote:
On Fri April 8 2005 11:30, Tony Finch wrote:
On Tue, 5 Apr 2005, Bruce Lilly wrote:
o Architecturally, all messages must pass through at least one
Gateway (which may be implemented in conjunction with an MTA, MDA,
or even MUA). [this is necessary to accomplish MIME
message/partial reassembly as detailed in RFC 1344].
I don't think it's helpful to describe the MIME functionality in an
MUA as something to do with gatewaying because the MUA is not a
transport-level entity. It's only necessary for gateways to implement
MIME in order for them to properly handle the mismatch between
Internet email and some other email system, so the MIME handling is a
secondary feature rather than something fundamental to gateways.
Please see RFC 1344 sections "Fragmenting and Reassembling Large
Messages" and "Using or Removing External-Body Pointers" and then
look at http://www.kb.cert.org/vuls/id/836088. My initial response
upon hearing of that supposed "new" "exploit" are recorded at
http://lists.sans.org/pipermail/list/2002-September/054081.html
and I stand by those remarks.
That all addresses reassembly when gatewaying. I'm talking about a
situation without filtering and using only Internet protocols, where the
only place that needs to perform reassembly is the MUA, and there is
nothing performing the architectural role of gateway.
Sieve continues to evolve; there is a recent proposal for
"vacation"-like functionality; would you really like to receive a dozen
notifications because a message was fragmented in transit?
Sieve requires that a correspondent does not receive multiple copies of
the vacation notification within a reasonable period of a time (e.g. a
week) which deals with that problem.
Tony.
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