This is not only for CloudStack, but they are common issues when you are playing CloudStack regarding network. I often suffer these errors, there are some tips from my practice:
1. "No route to host" Most likely iptables rule prevents the port from accessing. First check iptables rule in your VM, then check SecurityGroup rules in CloudStack. Finally check the rules in host where the VM is running(in this case, please file a bug for SecurityGroup) 2. "Connection refused" The destination port is reachable, however, there is no application listens on that port 3. "Connection reset" The established connection has lost. Please correct me if you see anything wrong.
