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The following page has been changed by SteveLoughran: http://wiki.apache.org/hadoop/NoRouteNoHost The comment on the change is: Page on NoRouteToHost New page: = No Route to Host = You get a TCP No Route To Host Error -often wrapped in a Java {{{IOException}}}, when one machine on the network does not know how to send TCP packets to the machine specified. Some possible causes (not an exclusive list): * the hostname of the remote machine is wrong in the configuration files * the client's host table {{{//etc/hosts}}} has an invalid IPAddress for the target host. * the DNS server's host table has an invalid IPAddress for the target host. * the client's routing tables (In Linux, iptables) are wrong. * the DHCP server is publishing bad routing information. * client and server are on different subnets, and are not set up to talk to each other. This may be an accident, or it is to deliberately lock down the Hadoop cluster. None of these are Hadoop problems, they are network configuration/router issues. As it is your network, only you can find out and track down the problem.
