diff --git a/plugins/network/traffic_ipt b/plugins/network/traffic_ipt
index 4bef6c39..754693a8 100755
--- a/plugins/network/traffic_ipt
+++ b/plugins/network/traffic_ipt
@@ -139,9 +139,9 @@ fi
 
 if [ $ipv6 -ge $oldv6 ];
 then
-	diffv4=$(($ipv6 - $oldv6))
+	diffv6=$(($ipv6 - $oldv6))
 else
-	diffv4=$ipv6
+	diffv6=$ipv6
 fi
 
 echo "IPv4=$ipv4" > $MUNIN_STATEFILE