use socket/polling failures to detect unreachable server
Gracefully handle unreacable or restarted server
(from redmine: issue id 1886, created on 2014-10-07 by gmueller, closed on 2014-10-07)
Gracefully handle unreacable or restarted server
(from redmine: issue id 1886, created on 2014-10-07 by gmueller, closed on 2014-10-07)