Hi list,
I am trying to figure out how an IMAP server could corrupt
a message when it is saved to a 'Drafts' or 'postponed' folder.
mail client: pine-4.33 or sylpheed-0.8.0, on solaris2.6
mail server: microsoft exchange-5.5 (5.5.2655.37) on w2k
I thought I had this nailed when I was composing a message
that had the following construction in it:
<quote>
>From what I can see..
</quote>
which I postponed and when I reopened it and found it was
corrupted, in the "From" field of the mail header, that sentence
appeared. So I started to think that the server was parsing
the messages and breaking them at the wrong place.
I did some tcpdumps and realised that IMAP operates on the
message length, i.e. you do an APPEND foldername {697} to
save 697 bytes of a message. Here is a fragment of a successful
postponement, as viewed with tcpdump and 'ethereal'.
request > 000033 RLIST "" postponed-msgs
response < * 480 EXISTS
< 000033 OK LIST completed.
> 000034 RLIST "" postponed-msgs/ %
< 000034 OK LIST completed.
> 000035 APPEND postponed-msgs {697}
< + Ready for additional command text.
> Newsgroups:
< 000035 OK APPEND completed.
> 000036 RLIST "" %
....
However an unsuccessful postponenment (where the message gets
corrupted) looks about the same.
At some point however the server must make a decision about
what is header or envelope and what is body. The IMAP4r1 RFC
says that the client is supposed to structure the APPEND data
according to RFC822 (ie the client decides what is header and
what is body). However I'm unclear whether one is allowed to
APPEND more than a single message. Could it be that the server
is trying to parse the APPEND data for multiple messages and
getting it wrong, as I suggested above?
Is this a known bug in the exchange imap service?
I have asked the people who run our exchange server but got
nothing sensible from them, or from trawling the net (for
some weeks, off and on). I did find this (just now):
http://www.cs.washington.edu/lab/sw/email/pine-exchange.html#cc_bug
but is it the same problem? I can get corruption on messages as
short as 3967 bytes (possibly less) but the bug notice says this
only happens with long messages (~16kb and up).
And it happens with sylpheed, too, which I think is an independent
implementation of an IMAP client.
I have tcpdumps if they will help.
Cheers
Vincent McIntyre
Australia Telescope National Facility, CSIRO
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