diff --git a/includes/discovery/os/fortios.inc.php b/includes/discovery/os/fortios.inc.php
index 62584f2cb..d5138abe1 100644
--- a/includes/discovery/os/fortios.inc.php
+++ b/includes/discovery/os/fortios.inc.php
@@ -1,7 +1,7 @@
 <?php
 
 if (!$os) {
-    if (strstr($sysObjectId, '.1.3.6.1.4.1.12356.103.3')) {
+    if (strstr($sysObjectId, '.1.3.6.1.4.1.12356.103')) {
         $os = 'fortios';
     }
 }
diff --git a/includes/rewrites.php b/includes/rewrites.php
index da0623f11..2a71150f2 100644
--- a/includes/rewrites.php
+++ b/includes/rewrites.php
@@ -331,6 +331,7 @@ $rewrite_fortinet_hardware = array(
     '.1.3.6.1.4.1.12356.1688'        => 'FortiMail 2000A',
     '.1.3.6.1.4.1.12356.103.1.1000'  => 'FortiManager 100',
     '.1.3.6.1.4.1.12356.103.1.20000' => 'FortiManager 2000XL',
+    '.1.3.6.1.4.1.12356.103.1.3004'  => 'FortiManager 300D',
     '.1.3.6.1.4.1.12356.103.1.30000' => 'FortiManager 3000',
     '.1.3.6.1.4.1.12356.103.1.30002' => 'FortiManager 3000B',
     '.1.3.6.1.4.1.12356.103.1.4000'  => 'FortiManager 400',