diff --git a/tcp/reorderstream_test.go b/tcp/reorderstream_test.go
index 3ef952f..69b7482 100644
--- a/tcp/reorderstream_test.go
+++ b/tcp/reorderstream_test.go
@@ -31,10 +31,10 @@ func TestHandlerStreamIntegrityUnderReorder(t *testing.T) {
 	var want, got []byte
 	rb := make([]byte, mtu)
 	letter := byte('A')
-	for round := 0; round < rounds; round++ {
+	for round := range rounds {
 		// Capture this round's segments on the wire, one segment per write.
 		segs := make([][]byte, 0, nsegs)
-		for i := 0; i < nsegs; i++ {
+		for range nsegs {
 			payload := make([]byte, segSize)
 			for j := range payload {
 				payload[j] = letter
diff --git a/x/xnet/xnet_test.go b/x/xnet/xnet_test.go
index 5312cbf..77ac1d3 100644
--- a/x/xnet/xnet_test.go
+++ b/x/xnet/xnet_test.go
@@ -1216,7 +1216,7 @@ func TestEphemeralPortSequence(t *testing.T) {
 	}
 	const cycle = 16384
 	var seen [cycle]bool
-	for i := 0; i < cycle; i++ {
+	for i := range cycle {
 		port := s.ephemeralPort()
 		if port < 49152 {
 			t.Fatalf("port %d below dynamic range (RFC 6335)", port)