diff --git a/simulation/test_tracker.cpp b/simulation/test_tracker.cpp
index 4fbbf3f31..fc48c9b72 100644
--- a/simulation/test_tracker.cpp
+++ b/simulation/test_tracker.cpp
@@ -756,7 +756,7 @@ TORRENT_TEST(tracker_ipv6_argument)
 			TEST_CHECK(pos != std::string::npos || stop_event);
 			got_ipv6 |= pos != std::string::npos;
 			// make sure the IPv6 argument is url encoded
-			TEST_CHECK(req.substr(pos + 6, req.find_first_of(pos + 6, '&'))
+			TEST_CHECK(req.substr(pos + 6, req.find_first_of('&', pos + 6))
 				== "ffff%3a%3a1337");
 			return sim::send_response(200, "OK", 11) + "d5:peers0:e";
 		}
diff --git a/src/broadcast_socket.cpp b/src/broadcast_socket.cpp
index 1fb5e4e8f..99caf53e1 100644
--- a/src/broadcast_socket.cpp
+++ b/src/broadcast_socket.cpp
@@ -146,6 +146,8 @@ namespace libtorrent
 		tcp::socket test(ios);
 		error_code ec;
 		test.open(tcp::v6(), ec);
+		if (ec) return false;
+		test.bind(tcp::endpoint(address_v6::from_string("::1"), 0), ec);
 		return !bool(ec);
 #endif
 	}
diff --git a/test/test_tracker.cpp b/test/test_tracker.cpp
index 76acbacad..63cd13bb6 100644
--- a/test/test_tracker.cpp
+++ b/test/test_tracker.cpp
@@ -403,6 +403,8 @@ void test_udp_tracker(std::string const& iface, address tracker, tcp::endpoint c
 
 	// we should have announced the stopped event now
 	TEST_EQUAL(num_udp_announces(), prev_udp_announces + 2);
+
+	stop_udp_tracker();
 }
 
 TORRENT_TEST(udp_tracker_v4)
@@ -413,7 +415,10 @@ TORRENT_TEST(udp_tracker_v4)
 #if TORRENT_USE_IPV6
 TORRENT_TEST(udp_tracker_v6)
 {
-	test_udp_tracker("[::1]", address_v6::any(), ep("::1.3.3.7", 1337));
+	if (supports_ipv6())
+	{
+		test_udp_tracker("[::1]", address_v6::any(), ep("::1.3.3.7", 1337));
+	}
 }
 #endif
 
@@ -470,10 +475,7 @@ TORRENT_TEST(http_peers)
 	expected_peers.insert(ep("65.65.65.65", 16962));
 	expected_peers.insert(ep("67.67.67.67", 17476));
 #if TORRENT_USE_IPV6
-	if (supports_ipv6())
-	{
-		expected_peers.insert(ep("4545:4545:4545:4545:4545:4545:4545:4545", 17990));
-	}
+	expected_peers.insert(ep("4545:4545:4545:4545:4545:4545:4545:4545", 17990));
 #endif
 
 	TEST_EQUAL(peers.size(), expected_peers.size());
diff --git a/test/udp_tracker.cpp b/test/udp_tracker.cpp
index 5d59abe3f..53e99a2b5 100644
--- a/test/udp_tracker.cpp
+++ b/test/udp_tracker.cpp
@@ -174,7 +174,7 @@ struct udp_tracker
 			, std::bind(&udp_tracker::on_udp_receive, this, _1, _2, from, buffer, size));
 	}
 
-	udp_tracker(address iface)
+	explicit udp_tracker(address iface)
 		: m_udp_announces(0)
 		, m_socket(m_ios)
 		, m_port(0)
@@ -201,14 +201,15 @@ struct udp_tracker
 			return;
 		}
 
-		std::printf("%s: UDP tracker initialized on port %d\n", time_now_string(), m_port);
+		std::printf("%s: UDP tracker [%p] initialized on port %d\n"
+			, time_now_string(), this, m_port);
 
 		m_thread = std::make_shared<std::thread>(&udp_tracker::thread_fun, this);
 	}
 
 	void stop()
 	{
-		std::printf("%s: UDP tracker, stop\n", time_now_string());
+		std::printf("%s: UDP tracker [%p], stop\n", time_now_string(), this);
 		m_abort = true;
 		m_socket.cancel();
 		m_socket.close();
@@ -216,6 +217,8 @@ struct udp_tracker
 
 	~udp_tracker()
 	{
+		std::printf("%s: UDP tracker [%p], ~udp_tracker\n"
+			, time_now_string(), this);
 		m_ios.post(std::bind(&udp_tracker::stop, this));
 		if (m_thread) m_thread->join();
 	}
@@ -224,13 +227,6 @@ struct udp_tracker
 
 	int num_hits() const { return m_udp_announces; }
 
-	static void incoming_packet(error_code const& ec, size_t bytes_transferred, size_t *ret, error_code* error, bool* done)
-	{
-		*ret = bytes_transferred;
-		*error = ec;
-		*done = true;
-	}
-
 	void thread_fun()
 	{
 		char buffer[2000];
@@ -249,7 +245,7 @@ struct udp_tracker
 			return;
 		}
 
-		std::printf("UDP exiting UDP tracker thread\n");
+		std::printf("UDP exiting UDP tracker [%p] thread\n", this);
 	}
 };
 
@@ -257,6 +253,7 @@ std::shared_ptr<udp_tracker> g_udp_tracker;
 
 int start_udp_tracker(address iface)
 {
+	TORRENT_ASSERT(!g_udp_tracker);
 	g_udp_tracker.reset(new udp_tracker(iface));
 	return g_udp_tracker->port();
 }