Merge branch 'master' of https://github.com/2881099/FreeRedis

src/FreeRedis/Internal/DefaultRedisSocket.cs

@@ -182,10 +182,10 @@ public void Connect()
             {
                 ResetHost(Host);
 
-                IPEndPoint endpoint = IPAddress.TryParse(_ip, out var tryip) ?
-                    new IPEndPoint(tryip, _port) :
-                    new IPEndPoint(Dns.GetHostAddresses(_ip).FirstOrDefault() ?? IPAddress.Parse(_ip), _port);
-                var localSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+                EndPoint endpoint = ParseEndPoint(_ip, _port);
+                var localSocket = endpoint.AddressFamily == AddressFamily.InterNetworkV6 ? 
+                    new Socket(AddressFamily.InterNetworkV6, SocketType.Stream, ProtocolType.Tcp):
+                    new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
 
                 var asyncResult = localSocket.BeginConnect(endpoint, null, null);
                 if (!asyncResult.AsyncWaitHandle.WaitOne(ConnectTimeout, true))
@@ -268,5 +268,20 @@ public static KeyValuePair<string, int> SplitHost(string host)
 
             return new KeyValuePair<string, int>(host, 6379);
         }
+
+        private static EndPoint ParseEndPoint(string ip, int port)
+        {
+            if (IPAddress.TryParse(ip, out var tryip))
+            {
+                return new IPEndPoint(tryip, port);
+            }
+
+            if (Dns.GetHostAddresses(ip).Length == 0)
+            {
+                throw new Exception($"无法解析“{ip}”");
+            }
+
+            return new DnsEndPoint(ip, port);
+        }
     }
 }