Error Message:

Host is unreachable.

Explanation:

A socket operation was attempted to an unreachable target host. Winsock generates WSAENETUNREACH when it receives a "host unreachable" ICMP message from a router instead of WSAEHOSTUNREACH. The ICMP message means that the router cannot forward the IP datagram to the target host, possibly because it did not get a response to the ARP request (which might mean the destination host is down).

User Action:

Try to ping the destination host, to see if you get the same results (chances are, you will). Check the destination address itself; is it the one you wanted to go to? Check whether you have a router configured in your network system (your Winsock implementation). Do a traceroute to try to determine where the failure occurs along the route between your host and the destination host.