[sclug] Bizarre IMAP problem

[Darren Davison]

Hi,

I'm tearing my hair out over this one and wondered if someone might be able to
relieve some pain for me!

Trying to get mail from an IMAP server which happens to be MS Exchange
(ugh!) but the client is a linux laptop.  Connection is made over a Cisco
VPN but otherwise the IMAP traffic goes to the plain text port 143 with no TLS
involved.

Using several different clients, the same problem is 100% repeatable: folders
can be listed, messages in folders can be listed and message headers can be
retrieved but any attempt to retrieve a message body results in the connection
simply hanging until the client is killed.

Here's why I'm getting so stressed:

 * Verified this with Evolution, Thunderbird, Fetchmail and an interactive
   telnet session into the server.  So we can safely discount any client
   specific issues.

 * ALL of the above clients work perfectly against the same server from
   several other (linux) machines using the same VPN software.  So we can
   discount the VPN client and the Exchange server itself (unfortunately).

 * The connection ALWAYS chokes at PRECISELY the same point (see the telnet
   session transcript below) and this has been repeated dozens of times now.
   So I think it unlikely that transient network issues are to blame.

It seems like it's something deep rooted in this particular machine's setup,
but I'm clean out of ideas now.  Any thoughts??

Regards,
Darren.



here's the telnet transcript with sensitive info munged:

davisond at laptop ~ $ telnet 0.0.0.0 143
Trying 0.0.0.0...
Connected to 0.0.0.0.
Escape character is '^]'.
* OK Microsoft Exchange Server 2003 IMAP4rev1 server version 6.5.7226.0
(company.server.com) ready.
10 LOGIN davisond *********
10 OK LOGIN completed.
20 SELECT INBOX
* 11 EXISTS
* 0 RECENT
* FLAGS (\Seen \Answered \Flagged \Deleted \Draft $MDNSent)
* OK [PERMANENTFLAGS (\Seen \Answered \Flagged \Deleted \Draft $MDNSent)]
Permanent flags
* OK [UIDVALIDITY 6259] UIDVALIDITY value
20 OK [READ-WRITE] SELECT completed.
30 FETCH 1 ALL
* 1 FETCH (FLAGS (\Seen) INTERNALDATE "17-Aug-2005 00:22:19 +0100" RFC822.SIZE
11304 ENVELOPE ("Wed, 17 Aug 2005 00:21:06 +0100" "some subject"
(( remaining headers cut out ))
30 OK FETCH completed.
40 FETCH 1 BODY[TEXT]
* 1 FETCH (BODY[TEXT]

..and that's it.  Always at that exact point, the connection dries up and the
client hangs.


-- 

Darren Davison
Public Key: 0xDD356B0D
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