diff --git a/src/knx/data_link_layer.cpp b/src/knx/data_link_layer.cpp
index d2413dc8..8f51650c 100644
--- a/src/knx/data_link_layer.cpp
+++ b/src/knx/data_link_layer.cpp
@@ -48,6 +48,12 @@ void DataLinkLayer::dataIndicationToTunnel(CemiFrame& frame)
 {
     println("default dataIndicationToTunnel");
 }
+
+bool DataLinkLayer::isTunnelAddress(uint16_t addr)
+{
+    println("default IsTunnelAddress");
+    return false;
+}
 #endif
 
 void DataLinkLayer::dataRequestFromTunnel(CemiFrame& frame)
@@ -210,7 +216,7 @@ bool DataLinkLayer::sendTelegram(NPDU & npdu, AckType ack, uint16_t destinationA
 #endif
     tmpFrame.confirm(ConfirmNoError);
 
-    if(frame.sourceAddress() == _deviceObject.individualAddress() && mediumType() == DptMedium::KNX_TP1)    // quick fix only send to tunnel if we are the tpuart data link layer
+    if(frame.sourceAddress() == _deviceObject.individualAddress() && _networkLayerEntity.getEntityIndex() == 1)    // only send to tunnel if we are the secondary interface
         _cemiServer->dataIndicationToTunnel(tmpFrame);
 #endif
 
diff --git a/src/knx/data_link_layer.h b/src/knx/data_link_layer.h
index 554c98ce..a1da31e9 100644
--- a/src/knx/data_link_layer.h
+++ b/src/knx/data_link_layer.h
@@ -36,6 +36,7 @@ class DataLinkLayer
     virtual void dataRequestToTunnel(CemiFrame& frame);
     virtual void dataConfirmationToTunnel(CemiFrame& frame);
     virtual void dataIndicationToTunnel(CemiFrame& frame);
+    virtual bool isTunnelAddress(uint16_t addr);
 #endif
 #endif
 
diff --git a/src/knx/ip_data_link_layer.cpp b/src/knx/ip_data_link_layer.cpp
index cfdfadfe..6b64bd49 100644
--- a/src/knx/ip_data_link_layer.cpp
+++ b/src/knx/ip_data_link_layer.cpp
@@ -215,6 +215,18 @@ void IpDataLinkLayer::sendFrameToTunnel(KnxIpTunnelConnection *tunnel, CemiFrame
 
     _platform.sendBytesUniCast(tunnel->IpAddress, tunnel->PortData, req.data(), req.totalLength());
 }
+
+bool IpDataLinkLayer::isTunnelAddress(uint16_t addr)
+{
+    if(addr == 0)
+        return false; // 0.0.0 is not a valid tunnel address and is used as default value
+    
+    for(int i = 0; i < KNX_TUNNELING; i++)
+        if(tunnels[i].IndividualAddress == addr)
+            return true;
+
+    return false;
+}
 #endif
 
 void IpDataLinkLayer::loop()
diff --git a/src/knx/ip_data_link_layer.h b/src/knx/ip_data_link_layer.h
index 20396615..efd465c2 100644
--- a/src/knx/ip_data_link_layer.h
+++ b/src/knx/ip_data_link_layer.h
@@ -24,6 +24,7 @@ class IpDataLinkLayer : public DataLinkLayer
     void dataRequestToTunnel(CemiFrame& frame) override;
     void dataConfirmationToTunnel(CemiFrame& frame) override;
     void dataIndicationToTunnel(CemiFrame& frame) override;
+    bool isTunnelAddress(uint16_t addr) override;
 #endif
 
   private:
diff --git a/src/knx/network_layer_coupler.cpp b/src/knx/network_layer_coupler.cpp
index 46eff4a6..edaa9cc4 100644
--- a/src/knx/network_layer_coupler.cpp
+++ b/src/knx/network_layer_coupler.cpp
@@ -1,4 +1,5 @@
 #include "network_layer_coupler.h"
+#include "data_link_layer.h"
 #include "device_object.h"
 #include "router_object.h"
 #include "tpdu.h"
@@ -348,8 +349,9 @@ void NetworkLayerCoupler::routeDataIndividual(AckType ack, uint16_t destination,
         // if destination is not within our scope then send via primary interface, else via secondary interface
         uint8_t destIfidx = (Z != netaddr) ? kPrimaryIfIndex : kSecondaryIfIndex;
 #ifdef KNX_TUNNELING
-        if(isTunnelAddress(destination))
-            destIfidx = kSecondaryIfIndex;
+        if(destIfidx == kPrimaryIfIndex)
+            if(isTunnelAddress(destination))
+                destIfidx = kSecondaryIfIndex;
 #endif
         //print("NetworkLayerCoupler::routeDataIndividual local to s or p: ");
         //println(destIfidx);
@@ -587,10 +589,6 @@ void NetworkLayerCoupler::dataSystemBroadcastRequest(AckType ack, HopCountType h
 
 bool NetworkLayerCoupler::isTunnelAddress(uint16_t destination)
 {
-    _netLayerEntities[kSecondaryIfIndex].dataLinkLayer().mediumType();
-    // FIXME
-    if((destination / 0x100) == 0xFF)
-        return true;
-    
-    return false;
+    // tunnels are managed within the IpDataLinkLayer - kPrimaryIfIndex
+    return _netLayerEntities[kPrimaryIfIndex].dataLinkLayer().isTunnelAddress(destination);
 }
\ No newline at end of file
diff --git a/src/knx/network_layer_entity.cpp b/src/knx/network_layer_entity.cpp
index 7a7b2152..389f765c 100644
--- a/src/knx/network_layer_entity.cpp
+++ b/src/knx/network_layer_entity.cpp
@@ -18,6 +18,11 @@ DataLinkLayer& NetworkLayerEntity::dataLinkLayer()
     return *_dataLinkLayer;
 }
 
+NetworkLayer& NetworkLayerEntity::networkLayer()
+{
+    return _netLayer;
+}
+
 DptMedium NetworkLayerEntity::mediumType() const
 {
     return _dataLinkLayer->mediumType();
diff --git a/src/knx/network_layer_entity.h b/src/knx/network_layer_entity.h
index b35c0829..22599e4e 100644
--- a/src/knx/network_layer_entity.h
+++ b/src/knx/network_layer_entity.h
@@ -17,6 +17,7 @@ class NetworkLayerEntity
 
     void dataLinkLayer(DataLinkLayer& layer);
     DataLinkLayer& dataLinkLayer();
+    NetworkLayer& networkLayer();
 
     DptMedium mediumType() const;
     uint8_t getEntityIndex();
diff --git a/src/knx/tpuart_data_link_layer.cpp b/src/knx/tpuart_data_link_layer.cpp
index 9aeaf5e7..5ea43f99 100644
--- a/src/knx/tpuart_data_link_layer.cpp
+++ b/src/knx/tpuart_data_link_layer.cpp
@@ -702,6 +702,12 @@ void TpUartDataLinkLayer::addFrameTxQueue(CemiFrame& frame)
     }
 }
 
+bool TpUartDataLinkLayer::isTunnelAddress(uint16_t addr)
+{
+    println("TpDataLinkLayer::isTunnelAddress");
+    return false;
+}
+
 bool TpUartDataLinkLayer::isTxQueueEmpty()
 {
     if (_tx_queue.front == NULL)
diff --git a/src/knx/tpuart_data_link_layer.h b/src/knx/tpuart_data_link_layer.h
index 8070f4fc..7a0e9cad 100644
--- a/src/knx/tpuart_data_link_layer.h
+++ b/src/knx/tpuart_data_link_layer.h
@@ -31,7 +31,7 @@ class TpUartDataLinkLayer : public DataLinkLayer
     bool enabled() const;
     void setFrameRepetition(uint8_t nack, uint8_t busy);
     DptMedium mediumType() const override;
-
+    bool isTunnelAddress(uint16_t addr) override;
   private:
     bool _enabled = false;
     uint8_t* _sendBuffer = 0;