diff --git a/node/Mutex.hpp b/node/Mutex.hpp
index cbd805245..e0917f01e 100644
--- a/node/Mutex.hpp
+++ b/node/Mutex.hpp
@@ -38,7 +38,8 @@
 
 namespace ZeroTier {
 
-#if defined(__GNUC__) && (defined(__amd64) || defined(__amd64__) || defined(__x86_64) || defined(__x86_64__) || defined(__AMD64) || defined(__AMD64__) || defined(_M_X64))
+//#if defined(__GNUC__) && (defined(__amd64) || defined(__amd64__) || defined(__x86_64) || defined(__x86_64__) || defined(__AMD64) || defined(__AMD64__) || defined(_M_X64))
+#if 0
 
 // Inline ticket lock on x64 systems with GCC and CLANG (Mac, Linux) -- this is really fast as long as locking durations are very short
 class Mutex : NonCopyable
diff --git a/node/Node.hpp b/node/Node.hpp
index 82f35c56e..79284b639 100644
--- a/node/Node.hpp
+++ b/node/Node.hpp
@@ -284,7 +284,7 @@ private:
 	Address _remoteTraceTarget;
 	enum Trace::Level _remoteTraceLevel;
 
-	int64_t _now;
+	volatile int64_t _now;
 	int64_t _lastPingCheck;
 	int64_t _lastHousekeepingRun;
 	int64_t _lastMemoizedTraceSettings;
diff --git a/node/Topology.cpp b/node/Topology.cpp
index fa9868e9f..17a0eee4c 100644
--- a/node/Topology.cpp
+++ b/node/Topology.cpp
@@ -162,8 +162,8 @@ SharedPtr<Peer> Topology::getUpstreamPeer()
 	unsigned int bestq = ~((unsigned int)0);
 	const SharedPtr<Peer> *best = (const SharedPtr<Peer> *)0;
 
-	Mutex::Lock _l1(_peers_m);
-	Mutex::Lock _l2(_upstreams_m);
+	Mutex::Lock _l2(_peers_m);
+	Mutex::Lock _l1(_upstreams_m);
 
 	for(std::vector<Address>::const_iterator a(_upstreamAddresses.begin());a!=_upstreamAddresses.end();++a) {
 		const SharedPtr<Peer> *p = _peers.get(*a);
@@ -252,8 +252,8 @@ bool Topology::addWorld(void *tPtr,const World &newWorld,bool alwaysAcceptNew)
 	if ((newWorld.type() != World::TYPE_PLANET)&&(newWorld.type() != World::TYPE_MOON))
 		return false;
 
-	Mutex::Lock _l1(_upstreams_m);
 	Mutex::Lock _l2(_peers_m);
+	Mutex::Lock _l1(_upstreams_m);
 
 	World *existing = (World *)0;
 	switch(newWorld.type()) {
@@ -341,8 +341,8 @@ void Topology::addMoon(void *tPtr,const uint64_t id,const Address &seed)
 
 void Topology::removeMoon(void *tPtr,const uint64_t id)
 {
-	Mutex::Lock _l1(_upstreams_m);
 	Mutex::Lock _l2(_peers_m);
+	Mutex::Lock _l1(_upstreams_m);
 
 	std::vector<World> nm;
 	for(std::vector<World>::const_iterator m(_moons.begin());m!=_moons.end();++m) {
diff --git a/service/OneService.cpp b/service/OneService.cpp
index 487ff4d0f..7d254124b 100644
--- a/service/OneService.cpp
+++ b/service/OneService.cpp
@@ -825,7 +825,24 @@ public:
 				// Sync multicast group memberships
 				if ((now - lastTapMulticastGroupCheck) >= ZT_TAP_CHECK_MULTICAST_INTERVAL) {
 					lastTapMulticastGroupCheck = now;
-					Mutex::Lock _l(_nets_m);
+					std::vector< std::pair< uint64_t,std::pair< std::vector<MulticastGroup>,std::vector<MulticastGroup> > > > mgChanges;
+					{
+						Mutex::Lock _l(_nets_m);
+						mgChanges.reserve(_nets.size() + 1);
+						for(std::map<uint64_t,NetworkState>::const_iterator n(_nets.begin());n!=_nets.end();++n) {
+							if (n->second.tap) {
+								mgChanges.push_back(std::pair< uint64_t,std::pair< std::vector<MulticastGroup>,std::vector<MulticastGroup> > >(n->first,std::pair< std::vector<MulticastGroup>,std::vector<MulticastGroup> >()));
+								n->second.tap->scanMulticastGroups(mgChanges.back().second.first,mgChanges.back().second.second);
+							}
+						}
+					}
+					for(std::vector< std::pair< uint64_t,std::pair< std::vector<MulticastGroup>,std::vector<MulticastGroup> > > >::iterator c(mgChanges.begin());c!=mgChanges.end();++c) {
+						for(std::vector<MulticastGroup>::iterator m(c->second.first.begin());m!=c->second.first.end();++m)
+							_node->multicastSubscribe((void *)0,c->first,m->mac().toInt(),m->adi());
+						for(std::vector<MulticastGroup>::iterator m(c->second.second.begin());m!=c->second.second.end();++m)
+							_node->multicastUnsubscribe(c->first,m->mac().toInt(),m->adi());
+					}
+					/*
 					for(std::map<uint64_t,NetworkState>::const_iterator n(_nets.begin());n!=_nets.end();++n) {
 						if (n->second.tap) {
 							std::vector<MulticastGroup> added,removed;
@@ -836,6 +853,7 @@ public:
 								_node->multicastUnsubscribe(n->first,m->mac().toInt(),m->adi());
 						}
 					}
+					*/
 				}
 
 				// Sync information about physical network interfaces