My log file continued to show following lines every few minutes, and there was a server crash two days ago, i was wondering if this have something to do with the crash
Sep 10 03:35:44 secure imapd[12884]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 03:44:05 secure imapd[13172]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 03:52:25 secure imapd[13469]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 04:00:45 secure imapd[13773]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 04:09:06 secure imapd[14464]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 04:17:26 secure imapd[14705]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 04:25:46 secure imapd[14919]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 04:34:07 secure imapd[15116]: Logout user=??? domain=??? host=UNKNOWN
Sep 10 04:42:27 secure imapd[15295]: Logout user=??? domain=??? host=UNKNOWN