Apache.NMS.ActiveMQ.Transport.Tcp.TcpTransportFactory.DoConnect C# (CSharp) Method

        protected Socket DoConnect(string host, int port, string localAddress, int localPort)
        {
            Socket socket = null;
            IPAddress ipaddress;

            try
            {
                if(TryParseIPAddress(host, out ipaddress))
                {
                    socket = TryConnectSocket(ipaddress, port, localAddress, localPort);
                }
                else
                {
                    // Looping through the AddressList allows different type of connections to be tried
                    // (IPv6, IPv4 and whatever else may be available).
                    IPHostEntry hostEntry = GetIPHostEntry(host);

                    if(null != hostEntry)
                    {
                        // Prefer IPv6 first.
                        ipaddress = GetIPAddress(hostEntry, AddressFamily.InterNetworkV6);
                        socket = TryConnectSocket(ipaddress, port, localAddress, localPort);
                        if(null == socket)
                        {
                            // Try IPv4 next.
                            ipaddress = GetIPAddress(hostEntry, AddressFamily.InterNetwork);
                            socket = TryConnectSocket(ipaddress, port, localAddress, localPort);
                            if(null == socket)
                            {
                                // Try whatever else there is.
                                foreach(IPAddress address in hostEntry.AddressList)
                                {
                                    if(AddressFamily.InterNetworkV6 == address.AddressFamily
                                        || AddressFamily.InterNetwork == address.AddressFamily)
                                    {
                                        // Already tried these protocols.
                                        continue;
                                    }

                                    socket = TryConnectSocket(ipaddress, port, localAddress, localPort);
                                    if(null != socket)
                                    {
                                        ipaddress = address;
                                        break;
                                    }
                                }
                            }
                        }
                    }
                }

                if(null == socket)
                {
                    throw new SocketException();
                }
            }
            catch(Exception ex)
            {
                throw new NMSConnectionException(String.Format("Error connecting to {0}:{1}.", host, port), ex);
            }

            Tracer.DebugFormat("Connected to {0}:{1} using {2} protocol.", host, port, ipaddress.AddressFamily.ToString());
            return socket;
        }