diff --git a/src/www/interfaces.php b/src/www/interfaces.php
index b4cc01596..35aeb2ed3 100644
--- a/src/www/interfaces.php
+++ b/src/www/interfaces.php
@@ -576,6 +576,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     }
 } elseif ($_SERVER['REQUEST_METHOD'] === 'POST') {
     $pconfig = $_POST;
+
     $input_errors = array();
     if (!empty($_POST['if']) && !empty($a_interfaces[$_POST['if']])) {
         $if = $_POST['if'];
@@ -622,6 +623,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         if (isset($a_interfaces[$if]['wireless'])) {
             interface_sync_wireless_clones($a_interfaces[$if], false);
         }
+        $a_interfaces[$if]['descr'] = preg_replace('/[^a-z_0-9]/i', '', $pconfig['descr']);
 
         write_config("Interface {$pconfig['descr']}({$if}) is now disabled.");
         mark_subsystem_dirty('interfaces');
diff --git a/src/www/interfaces_assign.php b/src/www/interfaces_assign.php
index 33a8912a6..7293171c2 100644
--- a/src/www/interfaces_assign.php
+++ b/src/www/interfaces_assign.php
@@ -152,7 +152,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         $newifname = 'opt' . $i;
         $descr = !empty($_POST['new_entry_descr']) ? $_POST['new_entry_descr'] : 'OPT' . $i;
         $config['interfaces'][$newifname] = array();
-        $config['interfaces'][$newifname]['descr'] = $descr;
+        $config['interfaces'][$newifname]['descr'] = preg_replace('/[^a-z_0-9]/i', '', $descr);;
         $config['interfaces'][$newifname]['if'] = $_POST['if_add'];
         $interfaces = list_interfaces();
         if ($interfaces[$_POST['if_add']]['section'] == 'ppps.ppp') {