Outlook cant fetch mail from my qmail server, but testing it via telnet works fine
Jun 17th, 2004 12:05
Joseph Sullivan, Jonathan de Boyne Pollard, Stein Robert Roessaak, http://www.clansullivan.com/joseph/
There is a well-known problem with Microsoft Outlook Express,
whereby it fails to cope with messages that contain certain
patterns of data (in particular, lone carriage returns at the
ends of physical header lines). The error message that it
displays ("Your server has unexpectedly terminated the
connection.") tries to place the blame on the POP3 server, but
this is a Microsoft Outlook Express bug.
It isn't anything to do with "qmail" at all. "qmail" has a
deliberately transparent design. What comes out at the POP3
end is exactly what went in at the SMTP Relay end. The problem
here is that one MUA, at the sending end (and possibly in
combination with the MTS at the sending end), has generated a
message that causes problems for another MUA, Microsoft Outlook
Express, at the receiving end. This is a compatibility problem
between two MUAs, and nothing to do with "qmail".
You might think that MUAs shouldn't be creating such messages
(because they violate a requirement in section 2.3 of RFC
2822). In which case, you should complain to the author of the
generating MUA at the sending end, whatever that is, and have
that MUA fixed.
You might, on the other hand, think that recipient MUAs should
be robust, and not vulnerable to any unusual message contents.
("Do not trust data received from the network.", and all that.)
In which case, you should complain to the author of Microsoft
You might foolishly decide not to complain to Microsoft and sit
around asserting that "'qmail' should do something", justifying
this erroneous concept of how to fix a Microsoft Outlook
Express problem by stating that Microsoft doesn't fix such
things. However, this justification is patently false. In
2003, Microsoft issued several critical updates that fixed
vulnerabilities in its MUA softwares that were due to them not
being able to safely and robustly handle certain patterns of
-- Update: A patch for qmail is available at
http://www.clansullivan.com/joseph/ that partially fixes this problem.
while I may repeat that qmail is NOT causing the problem, many admins
nevertheless find themselves in a position of having to do something
about it. If this is you, grab the patch and apply it to qmail 1.03.
The patch will cause Qmail to reject with an error messages containing
an illegal (see RFC) 0D0D sequence.