diff --git a/includes/dhcp.php b/includes/dhcp.php
index 53a33535..7785ae4b 100755
--- a/includes/dhcp.php
+++ b/includes/dhcp.php
@@ -182,7 +182,7 @@ function updateDnsmasqConfig($iface,$status)
     $config = '# RaspAP '.$iface.' configuration'.PHP_EOL;
     $config .= 'interface='.$iface.PHP_EOL.
         'dhcp-range='.$_POST['RangeStart'].','.$_POST['RangeEnd'].
-        ',255.255.255.0,';
+        ','.$_POST['SubnetMask'].',';
     if ($_POST['RangeLeaseTimeUnits'] !== 'infinite') {
         $config .= $_POST['RangeLeaseTime'];
     }