The webmail server at roundcube.cs.helsinki.fi has been receiving constantly more than 15 new connections per second from one IP address for almost 22 hours. This has caused overloading which users have experienced as delays and "DATABASE CONNECTION FAILED" errors. This may have been caused by a browser gone wild but it is possible that somebody has tried to exploit the well known OpenSSL "heartbleed" bug.  However, roundcube.cs.helsinki.fi is not  (and has never been) vulnerable to this bug. The IP address involved has been blocked.