diff --git a/opnsense-carp-dhcp.php b/opnsense-carp-dhcp.php
index 517d042..11ebcdd 100644
--- a/opnsense-carp-dhcp.php
+++ b/opnsense-carp-dhcp.php
@@ -140,7 +140,7 @@ $config['interfaces'][$wanInterface]['gateway'] = $gatewayName;
 # setup gateway
 $gwCount = count($config['gateways']['gateway_item']);
 $config['gateways']['gateway_item'][$gwCount]['gateway'] = $gatewayIP;
-$config['gateways']['gateway_item'][$gwCount]['interface'] = $interface;
+$config['gateways']['gateway_item'][$gwCount]['interface'] = $wanInterface;
 $config['gateways']['gateway_item'][$gwCount]['name'] = $gatewayName;
 $config['gateways']['gateway_item'][$gwCount]['ipprotocol'] = 'inet';
 $config['gateways']['gateway_item'][$gwCount]['monitor_disable'] = 1;