Berkeley description: A socket operation was attempted
to an unreachable host.
WinSock description: Same as Berkeley. Unlike Berkeley,
however, WinSock v1.1 doesn't ascribe this error to any functions. In
it's place, WinSock uses the error WSAENETUNREACH, exclusively.
TCP/IP scenario: In BSD-compatible implementations, the
local network system generates this error if there isn't a default route
configured. Typically, though, WinSock generates WSAENETUNREACH when it
receives a "host unreachable" ICMP message from a router
instead of WSAEHOSTUNREACH. The ICMP message means that the router can't
forward the IP datagram, possibly because it didn't get a response to
the ARP request (which might mean the destination host is down).
User suggestions: see WSAENETUNREACH for details
See also: WSAENETUNREACH