[CentOS] dovecot informational/error messages?

Fri Nov 22 14:58:22 UTC 2013
Timothy Murphy <gayleard at eircom.net>

Luigi Rosa wrote:

>> Nov 22 13:06:56 grover dovecot: imap-login: Disconnected (no auth
>> attempts): rip=, lip=, TLS: Disconnected
>> every second on my CentOS-6.4 server. Is this purely an informational
>> message? Or is it an error message? And in either case, how can I stop
>> the flood of messages?
> If is a Windows host, it could be infected; had a similar
> issue with one of my customers.

Thanks for your response.
But in fact it is a Linux laptop, running KMail.

> In any case, that log entry says that is opening a TCP
> connection to IMAP port of and closing it without any IMAP
> handshake

I've managed to stop the flood, 
though I'm not sure which of the steps I took had this effect.
1) I created a self-signed certificates /etc/pki/dovecot/certs/dovecot.pem
and /etc/pki/dovecot/private/dovecot.pem on the server, 
and  copied the first to /etc/pki/dovecot/certs and /etc/pki/tls/certs
on the laptop.
(I already had standard signed TLS certificates on both.)

2) I found that KMail on the laptop had the connection setting 
set to SSL/TLS on port 993, which I changed to STARTTLS on port 143.

3) I re-started dovecot on the server

4) I re-booted the laptop.

Now the flood of messages in /var/log/maillog seems to have stopped.