diff --git a/p2p/nat/nat_test.go b/p2p/nat/nat_test.go
index 8dd5644fd6..8b584ed55d 100644
--- a/p2p/nat/nat_test.go
+++ b/p2p/nat/nat_test.go
@@ -69,10 +69,10 @@ func TestAutoDiscRace(t *testing.T) {
 func TestParseStun(t *testing.T) {
 	testcases := []struct {
 		natStr string
-		want   *stun
+		want   STUN
 	}{
-		{"stun", &stun{serverList: strings.Split(stunDefaultServers, "\n")}},
-		{"stun:1.2.3.4:1234", &stun{serverList: []string{"1.2.3.4:1234"}}},
+		{"stun", STUN{stun: stun{serverList: strings.Split(stunDefaultServers, "\n")}}},
+		{"stun:1.2.3.4:1234", STUN{stun: stun{serverList: []string{"1.2.3.4:1234"}}}},
 	}
 
 	for _, tc := range testcases {
@@ -80,7 +80,7 @@ func TestParseStun(t *testing.T) {
 		if err != nil {
 			t.Errorf("should no err, but get %v", err)
 		}
-		stun := nat.(*stun)
+		stun := nat.(STUN)
 		assert.Equal(t, stun.serverList, tc.want.serverList)
 	}
 }
diff --git a/p2p/nat/stun.go b/p2p/nat/stun.go
index 0c5cec4bcc..270c5a30cc 100644
--- a/p2p/nat/stun.go
+++ b/p2p/nat/stun.go
@@ -54,7 +54,7 @@ func newSTUN(serverAddr string) (Interface, error) {
 		}
 		s.serverList = []string{serverAddr}
 	}
-	return s, nil
+	return STUN{stun: *s}, nil
 }
 
 func (s stun) String() string {