dovecot - Sep 2009 - Disconnected: Too many invalid IMAP commands

Greetings, I'm having big issues here, hope you can help me?

Ubuntu Server 8.04, postfix 2.5.1, dovecot 1.0.10, postfixadmin (MySQL+ 
virtual users)?

I am trying to move e-mails from an old IMAP account to my new dovecot 
IMAP server accounts.
The old server is EIMS (Eudora Internet Mail Server, so a sort of mbox 
format)?
I move messages by drag 'n' dropping in Mozilla Thunderbird.

No problems with messages under 4MB size (there are huge messages, up to 
25MB), but as soon as I try to move messages from 4MB and up, the 
connection hangs, nothing happens, the application becomes barely 
responsive, I have quit and re-open it to make it behave properly.

In the logs, I read (user and IPs are fake, here):

Sep 18 07:52:06 in dovecot: imap-login: Login: user=<user at my-domain>, 
method=PLAIN, rip=123.123.123.123, lip=123.123.123.123
Sep 18 07:52:06 in dovecot: IMAP(user at my-domain): Disconnected: Too many 
invalid IMAP commands.


Could it be a client (Thunderbird) issue?
I have tried with Apple Mail 4.1, same problem, same logs.

Could it be a quota limit (googling around, I read that sometimes the 
error may be triggered by dovecot when exceeding the quota limit)
Accout usage is actually at 1%?

Could drag 'n' drop be the wrong way to have things done?
I have also downloaded the huge e-mails from EIMS to Thunderbird Local 
Folders, the problem arises when I try to upload, so the culprit seems 
to be the new "system".


I really need help at this point? any hints?

Thanks in advance for any help you will offer.

Gabriele

On 9/18/2009, Gabriele (listarolo_dovecot at musimac.it)
wrote:
> dovecot 1.0.10
This is really old... it is very likely that upgrading dovecot to a more
current build - either 1.1.19, or better, 1.2.5 - will solve your
problem, but would be recommended anyway...

-- 

Best regards,

Charles

On Sep 18, 2009, at 11:52 AM, Gabriele wrote:
> No problems with messages under 4MB size (there are huge messages,  
> up to 25MB), but as soon as I try to move messages from 4MB and up,  
> the connection hangs, nothing happens, the application becomes  
> barely responsive, I have quit and re-open it to make it behave  
> properly.
Do you have some kind of a software firewall or antivirus in the  
middle? Those often cause problems.

But like Matthias mentioned, looking at the IMAP traffic would be  
helpful. For example with http://wiki.dovecot.org/Debugging/Rawlog

I was never meant to start a flame, so forgive me if I didn't observe 
the list guidelines.

The issue is solved now, it was a simple firewall (anti-malware setting) 
issue?

This runs against distro vs distro arguments, version vs version, etc.

Before writing to this list I already Googled, contacted a couple of 
Ubuntu forums, a couple of independent lists, to no avail. I either had 
no reply, or have been told to upgrade, to change distro, to compile vs 
using binaries, to switch to gentoo, etc. etc.

"old stable" isn't always cause of issues, in general, although I
might
agree with many of your statements and observations.

Thanks for your time, guys! :-)
Gabriele