diff --git a/default.inc b/default.inc
index a0f3969..3ca1967 100755
--- a/default.inc
+++ b/default.inc
@@ -34,6 +34,12 @@ IPprefix_by_netmask () {
        let c+=$((x%2)) 'x>>=1'
    done
    echo $c ; }
+   
+ALLOWED_NETWORKS="10.10.0.0/16 10.5.0.0/20 192.168.5.0/24"
+
+IP_ALLOWED() {
+	grepcidr "${ALLOWED_NETWORKS}" <(echo "${1}") >/dev/null && echo "true" || echo "false"
+}
 
 if type apt &>/dev/null; then
 	ATYPE="apt"