--- a/response.c
+++ b/response.c
@@ -117,32 +117,32 @@
   }
 
   snprintf(buf2, BUFSIZE, " %d %s", this_host->count, inet_ntoa(this_host->shost));
-  strncat(buf, buf2, BUFSIZE);
+  strncat(buf, buf2, BUFSIZE -1);
 
   if (opt.dst_ip) {
     snprintf(buf2, BUFSIZE, " %s", inet_ntoa(this_host->dhost));
-    strncat(buf, buf2, BUFSIZE);
+    strncat(buf, buf2, BUFSIZE -1);
   } else {
     strncat(buf, " -", BUFSIZE);
   }
 
   if (opt.proto) {
     snprintf(buf2, BUFSIZE, " %d", this_host->protocol);
-    strncat(buf, buf2, BUFSIZE);
+    strncat(buf, buf2, BUFSIZE -1);
   } else {
     strncat(buf, " -", BUFSIZE);
   }
 
   if (opt.src_port) {
     snprintf(buf2, BUFSIZE, " %d", this_host->sport);
-    strncat(buf, buf2, BUFSIZE);
+    strncat(buf, buf2, BUFSIZE -1);
   } else {
     strncat(buf, " -", BUFSIZE);
   }
 
   if (opt.dst_port) {
     snprintf(buf2, BUFSIZE, " %d", this_host->dport);
-    strncat(buf, buf2, BUFSIZE);
+    strncat(buf, buf2, BUFSIZE -1);
   } else {
     strncat(buf, " -", BUFSIZE);
   }