diff --git a/libnetutil/PacketParser.cc b/libnetutil/PacketParser.cc
index 73758712b..67af40b17 100644
--- a/libnetutil/PacketParser.cc
+++ b/libnetutil/PacketParser.cc
@@ -1126,24 +1126,28 @@ bool PacketParser::is_response(PacketElement *sent, PacketElement *rcvd){
       /* So far we've verified that the ICMP error contains an IP datagram that matches
        * what we sent. Now, let's find the upper layer ICMP header (skip extension
        * headers until we find ICMP) */
-      ICMPHeader *inner_icmp=(ICMPHeader *)iperror->getNextElement();
-      while(inner_icmp!=NULL){
-        if(inner_icmp->protocol_id()==HEADER_TYPE_ICMPv4 || inner_icmp->protocol_id()==HEADER_TYPE_ICMPv6 ){
+
+      iperror = dynamic_cast<NetworkLayerElement *>(iperror->getNextElement());
+      while(iperror!=NULL){
+        if(iperror->protocol_id()==HEADER_TYPE_ICMPv4 || iperror->protocol_id()==HEADER_TYPE_ICMPv6 ){
             break;
         }else{
-            inner_icmp=(ICMPHeader *)inner_icmp->getNextElement();
+          iperror = dynamic_cast<NetworkLayerElement *>(iperror->getNextElement());
         }
       }
-      if(inner_icmp==NULL)
+      if(iperror==NULL)
         return false;
 
       /* If we get here it means that we've found an ICMP header inside the
        * ICMP error message that we received. First of all, check that the
        * ICMP version matches what we sent. */
-      if(sent_layer4->protocol_id() != inner_icmp->protocol_id())
+      if(sent_layer4->protocol_id() != iperror->protocol_id())
         return false;
 
       /* Make sure ICMP type and code match  */
+      ICMPHeader *inner_icmp = dynamic_cast<ICMPHeader *>(iperror);
+      if (inner_icmp == NULL)
+        return false;
       if( ((ICMPHeader*)sent_layer4)->getType() != inner_icmp->getType() )
         return false;
       if( ((ICMPHeader*)sent_layer4)->getCode() != inner_icmp->getCode() )