Cyrus IMAP / Outlook Problem

[Phil Pennock]

On 2006-11-02 at 08:04 -0500, cbobb wrote:
> I keep getting the following error from and outlook 2003 client when the
> user is trying to view or look at emails either with or without file
> attachments.  It is not all messages just particular ones, usually with a
> file attachment:
> 
> The server did not respond to this IMAP command before the connection was
> terminated.

Sounds like your network connection is fine until you try to max out the
packet-size with large data transfers.  Which smells like a Path MTU
Discovery problem.

Do you have a firewall inbetween the IMAP server and the IMAP clients?
Is it possibly dropping fragmented packets, or stripping out all ICMP
errors?  You need ICMP "fragmentation needed and DF set", so that Path
MTU Discovery can function.  If you don't have control over the
firewalls, then you can band-aid around it by reducing the MTU
configured on the relevant network interface on the IMAP server.  That
in no way fixes the problem, but it might be just enough to bypass it
and provide evidence that the firewalls are broken, to get a longer-term
proper fix.

Regards,
-- 
"Everything has three factors: politics, money, and the right way to do it.
 In that order."  -- Gary Donahue