diff --git a/libnetutil/IPv4Header.h b/libnetutil/IPv4Header.h
index 83a91e0fd..6adc474dc 100644
--- a/libnetutil/IPv4Header.h
+++ b/libnetutil/IPv4Header.h
@@ -249,6 +249,7 @@ class IPv4Header : public NetworkLayerElement {
         u8 getNextProto() const;
         int setNextHeader(u8 val);
         u8 getNextHeader() const;
+        virtual u8 getNextHeader(){return 0;}
 
         /* Checksum */
         int setSum();
@@ -261,16 +262,18 @@ class IPv4Header : public NetworkLayerElement {
         int setDestinationAddress(struct in_addr d);
         const u8 *getDestinationAddress() const;
         struct in_addr getDestinationAddress(struct in_addr *result) const;
-
+        virtual u8 *getDestinationAddress(){return NULL;}
 
         /* Source IP */
         int setSourceAddress(u32 d);
         int setSourceAddress(struct in_addr d);
         const u8 *getSourceAddress() const;
         struct in_addr getSourceAddress(struct in_addr *result) const;
+        virtual u8 *getSourceAddress(){return NULL;}
 
         u16 getAddressLength() const;
-
+        virtual u16 getAddressLength(){return 0;}
+        
         /* IP Options */
         int setOpts(const char *txt);
         int setOpts(u8 *opts_buff,  u32 opts_len);
diff --git a/libnetutil/IPv6Header.h b/libnetutil/IPv6Header.h
index 7ab47ebcc..b86a3f33c 100644
--- a/libnetutil/IPv6Header.h
+++ b/libnetutil/IPv6Header.h
@@ -213,7 +213,8 @@ class IPv6Header : public NetworkLayerElement {
         int setNextHeader(u8 val);
         int setNextHeader(const char *p);
         u8 getNextHeader() const;
-        
+        virtual u8 getNextHeader(){return 0;}
+
         /* Hop Limit */
         int setHopLimit(u8 val);
         u8 getHopLimit() const;
@@ -223,14 +224,17 @@ class IPv6Header : public NetworkLayerElement {
         int setSourceAddress(struct in6_addr val);
         const u8 *getSourceAddress() const;
         struct in6_addr getSourceAddress(struct in6_addr *result) const;
-        
+        virtual u8 *getSourceAddress(){return NULL;}
+
         /* Destination Address*/
         int setDestinationAddress(u8 *val);
         int setDestinationAddress(struct in6_addr val);
         const u8 *getDestinationAddress() const;
         struct in6_addr getDestinationAddress(struct in6_addr *result) const;
+        virtual u8 *getDestinationAddress(){return NULL;}
 
         u16 getAddressLength() const;
+        virtual u16 getAddressLength(){return 0;}
 };
 
 #endif