diff --git a/src/internet-node/ipv4.cc b/src/internet-node/ipv4.cc
index d049edcd7..6a0697290 100644
--- a/src/internet-node/ipv4.cc
+++ b/src/internet-node/ipv4.cc
@@ -42,7 +42,7 @@ namespace ns3 {
 
 const uint16_t Ipv4::PROT_NUMBER = 0x0800;
 
-Ipv4::Ipv4(Node *node)
+Ipv4::Ipv4(Ptr<Node> node)
   : L3Protocol (PROT_NUMBER, 4),
     m_nInterfaces (0),
     m_defaultTtl (64),
@@ -51,12 +51,9 @@ Ipv4::Ipv4(Node *node)
     m_node (node)
 {
   SetupLoopback ();
-  m_node->Ref ();
 }
 Ipv4::~Ipv4 ()
-{
-  DoDispose ();
-}
+{}
 
 void 
 Ipv4::DoDispose (void)
@@ -83,11 +80,7 @@ Ipv4::DoDispose (void)
       delete m_defaultRoute;
       m_defaultRoute = 0;
     }
-  if (m_node != 0)
-    {
-      m_node->Unref ();
-      m_node = 0;
-    }
+  m_node = 0;
   L3Protocol::DoDispose ();
 }
 
diff --git a/src/internet-node/ipv4.h b/src/internet-node/ipv4.h
index 84b63bf95..b041b0e78 100644
--- a/src/internet-node/ipv4.h
+++ b/src/internet-node/ipv4.h
@@ -27,6 +27,7 @@
 #include "ns3/callback-trace-source.h"
 #include "ns3/array-trace-resolver.h"
 #include "ns3/ipv4-address.h"
+#include "ns3/ptr.h"
 #include "l3-protocol.h"
 
 namespace ns3 {
@@ -58,7 +59,7 @@ public:
   };
   typedef ArrayTraceResolver<Ipv4Interface>::Index InterfaceIndex;
 
-  Ipv4(Node *node);
+  Ipv4(Ptr<Node> node);
   virtual ~Ipv4 ();
 
   /**
@@ -240,7 +241,7 @@ private:
   HostRoutes m_hostRoutes;
   NetworkRoutes m_networkRoutes;
   Ipv4Route *m_defaultRoute;
-  Node *m_node;
+  Ptr<Node> m_node;
   CallbackTraceSource<Packet const &, uint32_t> m_txTrace;
   CallbackTraceSource<Packet const &, uint32_t> m_rxTrace;
   CallbackTraceSource<Packet const &> m_dropTrace;