WSAENETUNREACH - Error 10051

Question/Problem: Network is unreachable.

Answer/Solution: A socket operation was attempted to an unreachable network.

TCP/IP scenario: The local network system can generate this error if there is no a default route configured. Typically though, Winsock generates this error when it receives a "host unreachable" ICMP message from a router. The ICMP message means that a router cannot forward the IP datagram, possibly because it did not get a response to an ARP request (which might mean the destination host is down). Note: this error may also result if you try to send a multicast packet and the default gateway does not support multicast (check your interface configuration).