diff --git a/tun.go b/tun.go
index 1706ef9..f6252da 100644
--- a/tun.go
+++ b/tun.go
@@ -26,6 +26,7 @@ type tunHandler struct {
 	raddr   string
 	options *HandlerOptions
 	ipNet   *net.IPNet
+	routes  sync.Map
 }
 
 // TunHandler creates a handler for tun tunnel.
@@ -97,7 +98,6 @@ func (h *tunHandler) createTun() (conn net.Conn, err error) {
 }
 
 func (h *tunHandler) transportTun(tun net.Conn, conn net.PacketConn, raddr net.Addr) error {
-	var routes sync.Map
 	errc := make(chan error, 1)
 
 	go func() {
@@ -130,7 +130,7 @@ func (h *tunHandler) transportTun(tun net.Conn, conn net.PacketConn, raddr net.A
 				}
 
 				addr := raddr
-				if v, ok := routes.Load(header.Dst.String()); ok {
+				if v, ok := h.routes.Load(header.Dst.String()); ok {
 					addr = v.(net.Addr)
 				}
 				if addr == nil {
@@ -195,11 +195,11 @@ func (h *tunHandler) transportTun(tun net.Conn, conn net.PacketConn, raddr net.A
 				}
 
 				if h.ipNet != nil && h.ipNet.IP.Equal(header.Src.Mask(h.ipNet.Mask)) {
-					if actual, loaded := routes.LoadOrStore(header.Src.String(), addr); loaded {
+					if actual, loaded := h.routes.LoadOrStore(header.Src.String(), addr); loaded {
 						if actual.(net.Addr).String() != addr.String() {
 							log.Logf("[tun] %s <- %s: update route: %s -> %s (old %s)",
 								tun.LocalAddr(), addr, header.Src, addr, actual.(net.Addr))
-							routes.Store(header.Src.String(), addr)
+							h.routes.Store(header.Src.String(), addr)
 						}
 					} else {
 						log.Logf("[tun] %s: new route: %s -> %s", tun.LocalAddr(), header.Src, addr)
diff --git a/tun_windows.go b/tun_windows.go
index aa68aa2..3aa71ea 100644
--- a/tun_windows.go
+++ b/tun_windows.go
@@ -38,7 +38,7 @@ func createTun(cfg TunConfig) (conn net.Conn, ipNet *net.IPNet, err error) {
 		return
 	}
 
-	if err = addRoutes(ip.String(), cfg.Routes...); err != nil {
+	if err = addRoutes(ifce.Name(), cfg.Routes...); err != nil {
 		return
 	}
 
@@ -49,18 +49,16 @@ func createTun(cfg TunConfig) (conn net.Conn, ipNet *net.IPNet, err error) {
 	return
 }
 
-func addRoutes(ifIP string, routes ...string) error {
+func addRoutes(ifName string, routes ...string) error {
 	for _, route := range routes {
 		if route == "" {
 			continue
 		}
-		_, inet, err := net.ParseCIDR(route)
-		if err != nil {
-			return err
-		}
 
-		cmd := fmt.Sprintf("route ADD %s MASK %s %s",
-			inet.IP, ipMask(inet.Mask), ifIP)
+		deleteRoute(ifName, route)
+
+		cmd := fmt.Sprintf("netsh interface ip add route prefix=%s interface=%s store=active",
+			route, ifName)
 		log.Log("[tun]", cmd)
 		args := strings.Split(cmd, " ")
 		if er := exec.Command(args[0], args[1:]...).Run(); er != nil {
@@ -70,6 +68,13 @@ func addRoutes(ifIP string, routes ...string) error {
 	return nil
 }
 
+func deleteRoute(ifName string, route string) error {
+	cmd := fmt.Sprintf("netsh interface ip delete route prefix=%s interface=%s store=active",
+		route, ifName)
+	args := strings.Split(cmd, " ")
+	return exec.Command(args[0], args[1:]...).Run()
+}
+
 func ipMask(mask net.IPMask) string {
 	return fmt.Sprintf("%d.%d.%d.%d", mask[0], mask[1], mask[2], mask[3])
 }