diff --git a/scripts/shield-trigger b/scripts/shield-trigger
index 9aed262..65adf85 100755
--- a/scripts/shield-trigger
+++ b/scripts/shield-trigger
@@ -27,12 +27,9 @@ null_route() {
     # louzy detection of IPv4 or IPv6 address
     #
     TASK="$1"
-    INET=$(echo "$2" | sed 's/[0-9\.]//g')
-    if [ -z "$INET" ]
-    then
-        INET=""
-        GW="127.0.0.1"
-    else
+    INET=""
+    GW="127.0.0.1"
+    if [ "${2#*:}" != "$2" ] ; then
         INET="-f inet6"
         GW="::1"
     fi
diff --git a/scripts/shield-trigger-iptables b/scripts/shield-trigger-iptables
index 3f7e92b..51d446f 100755
--- a/scripts/shield-trigger-iptables
+++ b/scripts/shield-trigger-iptables
@@ -22,16 +22,8 @@
 #
 
 run_iptables() {
-    #
-    # louzy detection of IPv4 or IPv6 address
-    #
-    IPT=$(echo "$2" | sed 's/[0-9\.]//g')
-    if [ -z "$IPT" ]
-    then
-        IPT=iptables
-    else
-        IPT=ip6tables
-    fi
+    IPT="iptables"
+    [ "${2#*:}" != "$2" ] && IPT="ip6tables"
 
 # switch -A for iptables to -I
 if [ "$1" = "-A" ]