diff --git a/ssh/agent/client_test.go b/ssh/agent/client_test.go
index 93d3a9c..5fc47e5 100644
--- a/ssh/agent/client_test.go
+++ b/ssh/agent/client_test.go
@@ -180,9 +180,12 @@
 // therefore is buffered (net.Pipe deadlocks if both sides start with
 // a write.)
 func netPipe() (net.Conn, net.Conn, error) {
-	listener, err := net.Listen("tcp", ":0")
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
-		return nil, nil, err
+		listener, err = net.Listen("tcp", "[::1]:0")
+		if err != nil {
+			return nil, nil, err
+		}
 	}
 	defer listener.Close()
 	c1, err := net.Dial("tcp", listener.Addr().String())
@@ -200,6 +203,9 @@
 }
 
 func TestAuth(t *testing.T) {
+	agent, _, cleanup := startAgent(t)
+	defer cleanup()
+
 	a, b, err := netPipe()
 	if err != nil {
 		t.Fatalf("netPipe: %v", err)
@@ -208,9 +214,6 @@
 	defer a.Close()
 	defer b.Close()
 
-	agent, _, cleanup := startAgent(t)
-	defer cleanup()
-
 	if err := agent.Add(AddedKey{PrivateKey: testPrivateKeys["rsa"], Comment: "comment"}); err != nil {
 		t.Errorf("Add: %v", err)
 	}
diff --git a/ssh/handshake_test.go b/ssh/handshake_test.go
index 51a4c5a..91d4935 100644
--- a/ssh/handshake_test.go
+++ b/ssh/handshake_test.go
@@ -40,9 +40,12 @@
 // therefore is buffered (net.Pipe deadlocks if both sides start with
 // a write.)
 func netPipe() (net.Conn, net.Conn, error) {
-	listener, err := net.Listen("tcp", ":0")
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
 	if err != nil {
-		return nil, nil, err
+		listener, err = net.Listen("tcp", "[::1]:0")
+		if err != nil {
+			return nil, nil, err
+		}
 	}
 	defer listener.Close()
 	c1, err := net.Dial("tcp", listener.Addr().String())