diff --git a/app/access_controls/access_control_node_edit.php b/app/access_controls/access_control_node_edit.php
index 98adc4d5d7..d9a09c2026 100644
--- a/app/access_controls/access_control_node_edit.php
+++ b/app/access_controls/access_control_node_edit.php
@@ -53,6 +53,13 @@ if (count($_POST)>0 && strlen($_POST["persistformvar"]) == 0) {
 		//if (strlen($node_cidr) == 0) { $msg .= $text['message-required']." ".$text['label-node_cidr']."<br>\n"; }
 		//if (strlen($node_domain) == 0) { $msg .= $text['message-required']." ".$text['label-node_domain']."<br>\n"; }
 		//if (strlen($node_description) == 0) { $msg .= $text['message-required']." ".$text['label-node_description']."<br>\n"; }
+
+	// check IPv4 and IPv6 CIDR notation
+	  	$pattern4 = '/^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])(\/([0-9]|[1-2][0-9]|3[0-2]))$/';
+		$pattern6 = '/^s*((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]d|1dd|[1-9]?d)(.(25[0-5]|2[0-4]d|1dd|[1-9]?d)){3}))|:)))(%.+)?s*(\/([0-9]|[1-9][0-9]|1[0-1][0-9]|12[0-8]))$/';
+
+		if ($node_cidr != '' && (preg_match($pattern4, $node_cidr) == 0) && (preg_match($pattern6, $node_cidr) == 0)) { $msg .= $text['message-required']." ".$text['label-node_cidr']."<br>\n"; }
+	   
 		if (strlen($msg) > 0 && strlen($_POST["persistformvar"]) == 0) {
 			require_once "resources/header.php";
 			require_once "resources/persist_form_var.php";