diff --git a/forwarder.go b/forwarder.go
index a9f6705..72433bd 100644
--- a/forwarder.go
+++ b/forwarder.go
@@ -87,23 +87,24 @@ func (f *Forwarder) ForwardPacket(ipLayer *layers.IPv4, transportLayer gopacket.
 
 	// 获取源IP和端口
 	srcIP := ipLayer.SrcIP.String()
-	var srcPort int
+	var srcPort, dstPort int
 
 	// 根据传输层协议获取端口
 	switch t := transportLayer.(type) {
 	case *layers.TCP:
 		srcPort = int(t.SrcPort)
-		// dstPort = int(t.DstPort)
+		dstPort = int(t.DstPort)
 	case *layers.UDP:
 		srcPort = int(t.SrcPort)
-		// dstPort = int(t.DstPort)
+		dstPort = int(t.DstPort)
 	default:
 		// 不支持的传输层协议
 		return nil
 	}
 
-	// 查找转发规则
-	key := fmt.Sprintf("%s:%d", srcIP, srcPort)
+	// 查找转发规则, 按照目标端口查找并转发。
+	// 相当于做了一个端口映射。
+	key := fmt.Sprintf(":%d", dstPort) // srcIP, srcPort)
 	if forwardAddr, exists := f.natTable[key]; exists {
 		// 解析转发目标地址
 		addr, port, err := net.SplitHostPort(forwardAddr)