Re: [exim] Exim and POP3 Connector at Win2003 SBS Server

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Author: Tony Finch
Date:  
To: mwi78
CC: exim-users
Subject: Re: [exim] Exim and POP3 Connector at Win2003 SBS Server
On Tue, 12 Feb 2008, mwi78@??? wrote:
>
> my SBS server connects via pop3connector to my exim4 MTA and login via
> postmaster-account to any pop3 mailboxes. I have the problem, that some
> of these mail accounts fail to login.
>
> Der Fehler ist 1232 (Das Netzlaufwerk ist nicht erreichbar)


This is an Exchange problem, not an Exim problem, but the explanation is
too amusing not to post. Firstly, the error message and its pseudo
explanation "the network drive is not available" is complete crap. The
actual explanation can be found here:
http://support.microsoft.com/kb/280331
"This behavior occurs because one or more e-mail messages in the mailbox
of the POP3 server may contain Null characters and the POP3 Connector for
Small Business Server 4.5 is not able to download e-mail messages if they
contain Null characters."

We run Cyrus which also chokes on messages containing null characters. We
can't just reject these messages because legitimate but malformed messages
sometimes contain null characters. The main source of these messages is of
course Microsoft MTAs. This fills me with a mixture of glee and loathing.

To drag this back to some semblance of the topic of this mailing list, the
way we deal with this problem is to have the following setting on the
router that causes delivery to our Cyrus message store:

  transport = ${if ={0}{$body_zerocount} \
                   {hermes_lmtp} {hermes_lmtp_filter} }


The two hermes_lmtp transports are very similar, except the _filter
transport has an extra option at the end:

hermes_lmtp_filter:
  driver        = smtp
  protocol        = lmtp
  gethostbyname        = true
  rcpt_include_affixes    = true
  transport_filter    = /usr/bin/tr -d \\000


This is triggered pretty rarely, so the cost of the shell command doesn't
matter.

(It's also amusing that my emotion is schadenfreude, and I'm replying to
a German and I have an Austrian email address, but I don't speak German...)

Tony.
--
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