2011/12/4 Radim Kolar <hsn@sendmail.cz>
C:\cassandra\bin>nodetool -h repair
Starting NodeTool
Error connection to remote JMX agent!
java.rmi.ConnectException: Connection refused to host:; nested exc
eption is:
       java.net.ConnectException: Connection timed out: connect
       at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:601)

JMX is not very happy with hostname confusion. This is all on the setup of your DNS and system. Multi network systems cause issues. I see this often and have a small guide here: