The host '192.168.174.130' is unreachable. the host may be down..............
The host ‘192.168.174.130‘ is unreachable.
the host may be down,or there may be a problem with the network connection.
启动服务就可以正常访问了：service sshd start。此时输入service sshd status就会提示：openssh-daemon(pid 1844) is running.此时即可正常访问了。
the host may be down,or there may be a problem with the network connection.
Sometimes such problems can also be caused by a misconfigured firewall。
在SSH Secure Shell Client登陆的时候，出现了上述的提示，搞了好久，但是没发现错误的地方。网络是通的，即Linux和Windows可以相互的ping 。防火墙也关闭了。
后来在centos下输入service sshd status的时候，发现openssh-daemon is stopped。也就是没有启动sshd服务。启动服务就可以正常访问了：service sshd start。此时输入service sshd status就会提示：openssh-daemon(pid 1844) is running.此时即可正常访问了。
文章来自：http://blog.csdn.net/whq19890827/article/details/44535785