问题
I have a remote .Net web service that I have added as a web reference to my project via its WSDL. When I try to invoke a method on it I get the following exception:
A socket operation was attempted to an unreachable network 176.31.222.123:443
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)
The address it's trying to connect to is one of my own servers, and not only can I quite happily reach that IP address from my machine - other parts of the code that are also connecting to the same server work absolutely fine. It's only when using the web reference that it falls over.
Even weirder is that it doesn't happen on every machine, even between different machines on the same network give different results.
I'm almost certain something very daft is going on that will make me face palm, but does anyone have any clue about what on earth is going on?
来源：https://stackoverflow.com/questions/13782624/net-web-service-call-throws-a-network-unreachable-exception-yet-it-is-quite