--- nping/common_modified.cc
+++ nping/common_modified.cc
@@ -219,7 +219,9 @@
 
   int octet;
   struct sockaddr_in *sin = (struct sockaddr_in *) ss;
+#ifdef HAVE_IPV6
   struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) ss;
+#endif
 
   /* CHANGE: Commented out. See note at the end of the method */
   //startover: /* to handle nmap --resume where I have already
--- nping/EchoServer.cc
+++ nping/EchoServer.cc
@@ -211,7 +211,9 @@
   int one=1;                 /**< Dummy var for setsockopt() call      */
   int master_sd=-1;          /**< Master socket. Server listens on it  */
   struct sockaddr_in server_addr4;  /**< For our own IPv4 address      */
+#ifdef HAVE_IPV6
   struct sockaddr_in6 server_addr6; /**< For our own IPv6 address      */
+#endif
   int port = o.getEchoPort();
 
   /* Ignore SIGPIPE signal, received when a client disconnects suddenly and
@@ -220,6 +222,7 @@
     signal(SIGPIPE, SIG_IGN);
   #endif
 
+#ifdef HAVE_IPV6
   /* AF_INET6 */
   if( o.ipv6() ){
 
@@ -258,7 +261,9 @@
 
 
   /* AF_INET */
-  }else{
+  }else
+#endif
+  {
 
     /* Obtain a regular TCP socket for IPv4 */
     if( (master_sd=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP))<0 )
--- nping/NpingOps.cc
+++ nping/NpingOps.cc
@@ -1471,7 +1471,9 @@
  * sockaddr_in6 struct.  */
 struct sockaddr_storage *NpingOps::getSourceSockAddr(struct sockaddr_storage *ss){
   struct sockaddr_in *s4 = (struct sockaddr_in*)ss;
+#ifdef HAVE_IPV6
   struct sockaddr_in6 *s6 = (struct sockaddr_in6*)ss;
+#endif
   memset(ss, 0, sizeof(struct sockaddr_storage));
   if( this->getIPVersion() == IP_VERSION_4){
     if(this->spoofSource())
@@ -1483,6 +1485,7 @@
         s4->sin_port=htons(this->getSourcePort());
     else
         s4->sin_port=0;
+#ifdef HAVE_IPV6
   }
   else if (this->getIPVersion() == IP_VERSION_6){
     if(this->spoofSource())
@@ -1495,6 +1498,7 @@
         s6->sin6_port=htons(this->getSourcePort());
     else
         s6->sin6_port=0;
+#endif
   }else{
     outFatal(QT_3, "NpingOps::getSourceSockAddr(): IP version unset.");
   }
--- TargetGroup.cc
+++ TargetGroup.cc
@@ -426,7 +426,9 @@
 
   int octet;
   struct sockaddr_in *sin = (struct sockaddr_in *) ss;
+#ifdef HAVE_IPV6
   struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) ss;
+#endif
   startover: /* to handle nmap --resume where I have already
               * scanned many of the IPs */  
   assert(ss);