diff --git a/CHANGELOG b/CHANGELOG
index ff0ce10..a87ca95 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 proxy更新日志
 v5.2
 1.修复了HTTP(S)\SPS反向代理无法正常工作的问题.
+2.优化了智能判断,减少不必要的DNS解析.
 
 v5.1
 1.优化了kcp默认mtu配置,调整为450.
diff --git a/sdk/android-ios/dns.go b/sdk/android-ios/dns.go
index bb2dc4a..b08290d 100644
--- a/sdk/android-ios/dns.go
+++ b/sdk/android-ios/dns.go
@@ -76,7 +76,7 @@ func (s *DNS) InitService() (err error) {
 		nil,
 		&net.Dialer{
 			Timeout:   5 * time.Second,
-			KeepAlive: 5 * time.Second,
+			KeepAlive: 2 * time.Second,
 		},
 	)
 	if err != nil {
diff --git a/services/http/http.go b/services/http/http.go
index 9159c7b..a1a14aa 100644
--- a/services/http/http.go
+++ b/services/http/http.go
@@ -277,10 +277,11 @@ func (s *HTTP) callback(inConn net.Conn) {
 		} else if *s.cfg.Always {
 			useProxy = true
 		} else {
-			k := s.Resolve(address)
-			s.checker.Add(address, k)
-			//var n, m uint
-			useProxy, _, _ = s.checker.IsBlocked(k)
+			var isInMap bool
+			useProxy, isInMap, _, _ = s.checker.IsBlocked(address)
+			if !isInMap {
+				s.checker.Add(address, s.Resolve(address))
+			}
 			//s.log.Printf("blocked ? : %v, %s , fail:%d ,success:%d", useProxy, address, n, m)
 		}
 	}
diff --git a/services/socks/socks.go b/services/socks/socks.go
index 9069447..0f762d3 100644
--- a/services/socks/socks.go
+++ b/services/socks/socks.go
@@ -562,9 +562,11 @@ func (s *Socks) proxyTCP(inConn *net.Conn, methodReq socks.MethodsRequest, reque
 				if utils.IsIternalIP(host, *s.cfg.Always) {
 					useProxy = false
 				} else {
-					k := s.Resolve(request.Addr())
-					s.checker.Add(request.Addr(), k)
-					useProxy, _, _ = s.checker.IsBlocked(k)
+					var isInMap bool
+					useProxy, isInMap, _, _ = s.checker.IsBlocked(request.Addr())
+					if !isInMap {
+						s.checker.Add(request.Addr(), s.Resolve(request.Addr()))
+					}
 				}
 				if useProxy {
 					outConn, err = s.getOutConn(methodReq.Bytes(), request.Bytes(), request.Addr())
diff --git a/utils/structs.go b/utils/structs.go
index d098240..62eec27 100644
--- a/utils/structs.go
+++ b/utils/structs.go
@@ -132,24 +132,24 @@ func (c *Checker) isNeedCheck(item CheckerItem) bool {
 	}
 	return true
 }
-func (c *Checker) IsBlocked(address string) (blocked bool, failN, successN uint) {
+func (c *Checker) IsBlocked(address string) (blocked, isInMap bool, failN, successN uint) {
 	if c.domainIsInMap(address, true) {
 		//log.Printf("%s in blocked ? true", address)
-		return true, 0, 0
+		return true, true, 0, 0
 	}
 	if c.domainIsInMap(address, false) {
 		//log.Printf("%s in direct ? true", address)
-		return false, 0, 0
+		return false, true, 0, 0
 	}
 
 	_item, ok := c.data.Get(address)
 	if !ok {
 		//log.Printf("%s not in map, blocked true", address)
-		return true, 0, 0
+		return true, false, 0, 0
 	}
 	item := _item.(CheckerItem)
 
-	return item.FailCount >= item.SuccessCount, item.FailCount, item.SuccessCount
+	return item.FailCount >= item.SuccessCount, true, item.FailCount, item.SuccessCount
 }
 func (c *Checker) domainIsInMap(address string, blockedMap bool) bool {
 	u, err := url.Parse("http://" + address)