/// <summary> /// Creates a remote TCP connection through a proxy server to the destination host on the destination port. /// </summary> /// <param name="destinationHost">Destination host name or IP address.</param> /// <param name="destinationPort">Port number to connect to on the destination host.</param> /// <param name="timeout">Timeout duration for the Connect attempt.</param> /// <returns> /// Returns an open TcpClient object that can be used normally to communicate /// with the destination server /// </returns> /// <remarks> /// This method creates a connection to the proxy server and instructs the proxy server /// to make a pass through connection to the specified destination host on the specified /// port. /// </remarks> public TcpClient CreateConnection(string destinationHost, int destinationPort, TimeSpan timeout) { try { // if we have no connection, create one if (TcpClient == null) { if (string.IsNullOrEmpty(ProxyHost)) throw new ProxyException("ProxyHost property must contain a value."); if (ProxyPort <= 0 || ProxyPort > 65535) throw new ProxyException("ProxyPort value must be greater than zero and less than 65535"); // create new tcp client object to the proxy server TcpClient = tcpClientFactory(); // attempt to open the connection log.Write(EventType.Diagnostic, "Connecting to proxy at {0}:{1}", ProxyHost, ProxyPort); TcpClient.ConnectWithTimeout(ProxyHost, ProxyPort, timeout); } // send connection command to proxy host for the specified destination host and port SendConnectionCommand(destinationHost, destinationPort); // return the open proxied tcp client object to the caller for normal use return TcpClient; } catch (SocketException ex) { throw new ProxyException(string.Format(CultureInfo.InvariantCulture, "Connection to proxy host {0} on port {1} failed.", Utils.GetHost(TcpClient), Utils.GetPort(TcpClient)), ex); } }