[CentOS] dovecot informational/error messages?

Fri Nov 22 13:12:28 UTC 2013
Timothy Murphy <gayleard at eircom.net>

I'm getting the message

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?

Timothy Murphy  
e-mail: gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin 2, Ireland