diff --git a/includes/definitions/dsm.yaml b/includes/definitions/dsm.yaml
index f9a6e1b67f..9cb496b586 100644
--- a/includes/definitions/dsm.yaml
+++ b/includes/definitions/dsm.yaml
@@ -16,7 +16,7 @@ discovery:
       snmpget:
           oid: systemStatus.0
           mib: SYNOLOGY-SYSTEM-MIB
-          mibdir: synology
+          mib_dir: synology
           op: '!=='
           value: false
     -
diff --git a/includes/definitions/extrahop.yaml b/includes/definitions/extrahop.yaml
index 1aa2a756f1..ff8407c35a 100644
--- a/includes/definitions/extrahop.yaml
+++ b/includes/definitions/extrahop.yaml
@@ -15,6 +15,6 @@ discovery:
       snmpget:
           oid: extrahopInfoVersionString
           mib: EXTRAHOP-MIB
-          mibdir: extrahop
+          mib_dir: extrahop
           op: '!=='
           value: false
diff --git a/includes/definitions/pcoweb.yaml b/includes/definitions/pcoweb.yaml
index 96d4b35e63..2ab0e17daa 100644
--- a/includes/definitions/pcoweb.yaml
+++ b/includes/definitions/pcoweb.yaml
@@ -16,6 +16,6 @@ discovery:
       snmpget:
           oid: roomTemp.0
           mib: CAREL-ug40cdz-MIB
-          mibdir: carel
+          mib_dir: carel
           op: '!=='
           value: false
diff --git a/includes/functions.php b/includes/functions.php
index faf1dab5e0..e8f5049423 100644
--- a/includes/functions.php
+++ b/includes/functions.php
@@ -182,7 +182,7 @@ function checkDiscovery($device, $array, $sysObjectId, $sysDescr)
         } elseif ($key == 'snmpget') {
             $options = isset($value['options']) ? $value['options'] : '-Oqv';
             $mib = isset($value['mib']) ? $value['mib'] : null;
-            $mib_dir = isset($value['mibdir']) ? $value['mibdir'] : null;
+            $mib_dir = isset($value['mib_dir']) ? $value['mib_dir'] : null;
             $op = isset($value['op']) ? $value['op'] : 'contains';
 
             $get_value = snmp_get($device, $value['oid'], $options, $mib, $mib_dir);
diff --git a/tests/YamlTest.php b/tests/YamlTest.php
index 646ed67b6d..c84cb16209 100644
--- a/tests/YamlTest.php
+++ b/tests/YamlTest.php
@@ -49,7 +49,7 @@ class YamlTest extends \PHPUnit_Framework_TestCase
         'oid',
         'options',
         'mib',
-        'mibdir',
+        'mib_dir',
         'op',
         'value',
     );