diff --git a/SAM.cpp b/SAM.cpp
index 55eae222..2864cd6f 100644
--- a/SAM.cpp
+++ b/SAM.cpp
@@ -686,7 +686,7 @@ namespace client
 	{
 		{
 			std::lock_guard<std::mutex> lock(m_SocketsMutex);
-			for (auto sock : m_Sockets) {
+			for (auto& sock : m_Sockets) {
 				sock->CloseStream();
 			}
 		}
@@ -719,7 +719,7 @@ namespace client
 	{
 		m_IsRunning = false;
 		m_Acceptor.cancel ();
-		for (auto it: m_Sessions)
+		for (auto& it: m_Sessions)
 			it.second->CloseStreams ();
 		m_Sessions.clear ();
 		m_Service.stop ();
diff --git a/SAM.h b/SAM.h
index ef36f285..db08c5a0 100644
--- a/SAM.h
+++ b/SAM.h
@@ -154,7 +154,7 @@ namespace client
 			std::list<std::shared_ptr<SAMSocket> > l;
 			{
 				std::lock_guard<std::mutex> lock(m_SocketsMutex);
-				for( auto & sock : m_Sockets ) l.push_back(sock);
+				for(const auto& sock : m_Sockets ) l.push_back(sock);
 			}
 			return l;
 		}
diff --git a/SSU.cpp b/SSU.cpp
index f4277a5a..0c3662d3 100644
--- a/SSU.cpp
+++ b/SSU.cpp
@@ -237,9 +237,8 @@ namespace transport
 		std::map<boost::asio::ip::udp::endpoint, std::shared_ptr<SSUSession> > * sessions)
 	{
 		std::shared_ptr<SSUSession> session;	
-		for (auto it1: packets)
+		for (auto& packet: packets)
 		{
-			auto packet = it1;
 			try
 			{	
 				if (!session || session->GetRemoteEndpoint () != packet->from) // we received packet for other session than previous
@@ -431,11 +430,11 @@ namespace transport
 
 	void SSUServer::DeleteAllSessions ()
 	{
-		for (auto it: m_Sessions)
+		for (auto& it: m_Sessions)
 			it.second->Close ();
 		m_Sessions.clear ();
 
-		for (auto it: m_SessionsV6)
+		for (auto& it: m_SessionsV6)
 			it.second->Close ();
 		m_SessionsV6.clear ();
 	}
@@ -444,7 +443,7 @@ namespace transport
 	std::shared_ptr<SSUSession> SSUServer::GetRandomV4Session (Filter filter) // v4 only
 	{
 		std::vector<std::shared_ptr<SSUSession> > filteredSessions;
-		for (auto s :m_Sessions)
+		for (const auto& s :m_Sessions)
 			if (filter (s.second)) filteredSessions.push_back (s.second);
 		if (filteredSessions.size () > 0)
 		{
@@ -468,7 +467,7 @@ namespace transport
 	std::shared_ptr<SSUSession> SSUServer::GetRandomV6Session (Filter filter) // v6 only
 	{
 		std::vector<std::shared_ptr<SSUSession> > filteredSessions;
-		for (auto s :m_SessionsV6)
+		for (const auto& s :m_SessionsV6)
 			if (filter (s.second)) filteredSessions.push_back (s.second);
 		if (filteredSessions.size () > 0)
 		{
@@ -535,7 +534,7 @@ namespace transport
 			std::list<boost::asio::ip::udp::endpoint> newList;
 			size_t numIntroducers = 0;
 			uint32_t ts = i2p::util::GetSecondsSinceEpoch ();
-			for (auto it :m_Introducers)
+			for (const auto& it : m_Introducers)
 			{	
 				auto session = FindSession (it);
 				if (session && ts < session->GetCreationTime () + SSU_TO_INTRODUCER_SESSION_DURATION)
@@ -552,23 +551,20 @@ namespace transport
 			{
 				// create new
 				auto introducers = FindIntroducers (SSU_MAX_NUM_INTRODUCERS);
-				if (introducers.size () > 0)
+				for (const auto& it1: introducers)
 				{
-					for (auto it1: introducers)
+					const auto& ep = it1->GetRemoteEndpoint ();
+					i2p::data::RouterInfo::Introducer introducer;
+					introducer.iHost = ep.address ();
+					introducer.iPort = ep.port ();
+					introducer.iTag = it1->GetRelayTag ();
+					introducer.iKey = it1->GetIntroKey ();
+					if (i2p::context.AddIntroducer (introducer))
 					{
-						auto& ep = it1->GetRemoteEndpoint ();
-						i2p::data::RouterInfo::Introducer introducer;
-						introducer.iHost = ep.address ();
-						introducer.iPort = ep.port ();
-						introducer.iTag = it1->GetRelayTag ();
-						introducer.iKey = it1->GetIntroKey ();
-						if (i2p::context.AddIntroducer (introducer))
-						{	
-							newList.push_back (ep);
-							if (newList.size () >= SSU_MAX_NUM_INTRODUCERS) break;
-						}	
-					}	
-				}	
+						newList.push_back (ep);
+						if (newList.size () >= SSU_MAX_NUM_INTRODUCERS) break;
+					}
+				}
 			}	
 			m_Introducers = newList;
 			if (m_Introducers.size () < SSU_MAX_NUM_INTRODUCERS)
@@ -637,7 +633,7 @@ namespace transport
 					it = m_PeerTests.erase (it);
 				}
 				else
-					it++;	 
+					++it;
 			}
 			if (numDeleted > 0)
 				LogPrint (eLogDebug, "SSU: ", numDeleted, " peer tests have been expired");
diff --git a/SSUData.cpp b/SSUData.cpp
index e802791d..e5abfd54 100644
--- a/SSUData.cpp
+++ b/SSUData.cpp
@@ -427,12 +427,12 @@ namespace transport
 				if (ts >= it->second->nextResendTime)
 				{	
 					if (it->second->numResends < MAX_NUM_RESENDS)
-					{	
+					{
 						for (auto& f: it->second->fragments)
-							if (f) 
+							if (f)
 							{
 								try
-								{	
+								{
 									m_Session.Send (f->buf, f->len); // resend
 									numResent++;
 								}
@@ -440,11 +440,11 @@ namespace transport
 								{
 									LogPrint (eLogWarning, "SSU: Can't resend data fragment ", ec.what ());
 								}
-							}	
+							}
 
 						it->second->numResends++;
 						it->second->nextResendTime += it->second->numResends*RESEND_INTERVAL;
-						it++;
+						++it;
 					}	
 					else
 					{
@@ -453,7 +453,7 @@ namespace transport
 					}	
 				}	
 				else
-					it++;
+					++it;
 			}
 			if (numResent < MAX_OUTGOING_WINDOW_SIZE)
 				ScheduleResend ();
@@ -487,7 +487,7 @@ namespace transport
 					it = m_IncompleteMessages.erase (it);
 				}	
 				else
-					it++;
+					++it;
 			}	
 			// decay
 			if (m_ReceivedMessages.size () > MAX_NUM_RECEIVED_MESSAGES ||
diff --git a/SSUSession.cpp b/SSUSession.cpp
index 4e095deb..bf4058a5 100644
--- a/SSUSession.cpp
+++ b/SSUSession.cpp
@@ -907,7 +907,7 @@ namespace transport
 	{
 		if (m_State == eSessionStateEstablished)
 		{
-			for (auto it: msgs)
+			for (const auto& it: msgs)
 				if (it) m_Data.Send (it);
 		}
 	}	
diff --git a/Streaming.cpp b/Streaming.cpp
index 3806d97d..90c363ea 100644
--- a/Streaming.cpp
+++ b/Streaming.cpp
@@ -247,7 +247,7 @@ namespace stream
 		}	
 		int nackCount = packet->GetNACKCount ();
 		for (auto it = m_SentPackets.begin (); it != m_SentPackets.end ();)
-		{			
+		{
 			auto seqn = (*it)->GetSeqn ();
 			if (seqn <= ackThrough)
 			{
@@ -263,7 +263,7 @@ namespace stream
 					if (nacked)
 					{
 						LogPrint (eLogDebug, "Streaming: Packet ", seqn, " NACK");
-						it++;
+						++it;
 						continue;
 					}	
 				}
@@ -412,7 +412,7 @@ namespace stream
 			}	
 			bool isEmpty = m_SentPackets.empty ();
 			auto ts = i2p::util::GetMillisecondsSinceEpoch ();
-			for (auto it: packets)
+			for (auto& it: packets)
 			{
 				it->sendTime = ts;
 				m_SentPackets.insert (it);
@@ -762,7 +762,7 @@ namespace stream
 				bool updated = false;	
 				if (expired && m_CurrentRemoteLease)
 				{
-					for (auto it: leases)
+					for (const auto& it: leases)
 						if ((it->tunnelGateway == m_CurrentRemoteLease->tunnelGateway) && (it->tunnelID != m_CurrentRemoteLease->tunnelID))
 						{
 							m_CurrentRemoteLease = it;
@@ -798,7 +798,7 @@ namespace stream
 		
 	StreamingDestination::~StreamingDestination ()
 	{
-		for (auto it: m_SavedPackets)
+		for (auto& it: m_SavedPackets)
 		{
 			for (auto it1: it.second) delete it1;
 			it.second.clear ();	
@@ -877,7 +877,7 @@ namespace stream
 			else // follow on packet without SYN
 			{
 				uint32_t receiveStreamID = packet->GetReceiveStreamID ();
-				for (auto it: m_Streams)
+				for (auto& it: m_Streams)
 					if (it.second->GetSendStreamID () == receiveStreamID)
 					{
 						// found
@@ -944,7 +944,7 @@ namespace stream
 		m_Owner->GetService ().post([acceptor, this](void)
 			{                            
 				m_Acceptor = acceptor;
-				for (auto it: m_PendingIncomingStreams)
+				for (auto& it: m_PendingIncomingStreams)
 					if (it->GetStatus () == eStreamStatusOpen) // still open?
 						m_Acceptor (it);
 				m_PendingIncomingStreams.clear ();
@@ -963,7 +963,7 @@ namespace stream
 		if (ecode != boost::asio::error::operation_aborted)
 		{
 			LogPrint (eLogWarning, "Streaming: Pending incoming timeout expired");
-			for (auto it: m_PendingIncomingStreams)
+			for (auto& it: m_PendingIncomingStreams)
 				it->Close ();
 			m_PendingIncomingStreams.clear ();
 		}	
diff --git a/Transports.cpp b/Transports.cpp
index 4ad53d7f..b1c174f6 100644
--- a/Transports.cpp
+++ b/Transports.cpp
@@ -112,7 +112,7 @@ namespace transport
 		m_Thread = new std::thread (std::bind (&Transports::Run, this));
 		// create acceptors
 		auto& addresses = context.GetRouterInfo ().GetAddresses ();
-		for (auto address : addresses)
+		for (const auto& address : addresses)
 		{
 			if (m_NTCPServer == nullptr && enableNTCP)
 			{
@@ -236,7 +236,7 @@ namespace transport
 		if (ident == i2p::context.GetRouterInfo ().GetIdentHash ())
 		{	
 			// we send it to ourself
-			for (auto it: msgs)
+			for (auto& it: msgs)
 				i2p::HandleI2NPMessage (it);
 			return;
 		}	
@@ -266,7 +266,7 @@ namespace transport
 		{	
 			if (it->second.delayedMessages.size () < MAX_NUM_DELAYED_MESSAGES)
 			{	
-				for (auto it1: msgs)
+				for (auto& it1: msgs)
 					it->second.delayedMessages.push_back (it1);
 			}
 			else
@@ -636,7 +636,7 @@ namespace transport
 					it = m_Peers.erase (it);
 				}
 				else
-					it++;
+					++it;
 			}
 			UpdateBandwidth (); // TODO: use separate timer(s) for it
 			if (i2p::context.GetStatus () == eRouterStatusTesting) // if still testing,	 repeat peer test
@@ -658,7 +658,7 @@ namespace transport
   {
     std::lock_guard<std::mutex> lock(m_FamilyMutex);
     m_TrustedFamilies.clear();
-    for ( auto fam : families )
+    for ( const auto& fam : families )
       m_TrustedFamilies.push_back(fam);
   }
 
diff --git a/Transports.h b/Transports.h
index 708c55e2..81063916 100644
--- a/Transports.h
+++ b/Transports.h
@@ -60,7 +60,7 @@ namespace transport
 
 		void Done ()
 		{
-			for (auto it: sessions)
+			for (auto& it: sessions)
 				it->Done ();
 		}	
 	};	
diff --git a/TunnelConfig.h b/TunnelConfig.h
index 7546c9b2..23417ed9 100644
--- a/TunnelConfig.h
+++ b/TunnelConfig.h
@@ -213,7 +213,7 @@ namespace tunnel
 			void CreatePeers (const Peers& peers)
 			{
 				TunnelHopConfig * prev = nullptr;
-				for (auto it: peers)
+				for (const auto& it: peers)
 				{
 					auto hop = new TunnelHopConfig (it);
 					if (prev)