diff --git a/admin/tool/behat/cli/util.php b/admin/tool/behat/cli/util.php
index b28f4fcb6b0..5c24cf8c05d 100644
--- a/admin/tool/behat/cli/util.php
+++ b/admin/tool/behat/cli/util.php
@@ -142,6 +142,9 @@ foreach ($vars as $var) {
     $CFG->{$var} = $CFG->{'behat_' . $var};
 }
 
+// Clean $CFG extra values before performing any action.
+behat_clean_init_config();
+
 $CFG->noemailever = true;
 $CFG->passwordsaltmain = 'moodle';
 
diff --git a/lib/behat/lib.php b/lib/behat/lib.php
index e35b0e6192c..42ed4418ffd 100644
--- a/lib/behat/lib.php
+++ b/lib/behat/lib.php
@@ -141,3 +141,29 @@ function behat_error_handler($errno, $errstr, $errfile, $errline, $errcontext) {
     // Also use the internal error handler so we keep the usual behaviour.
     return false;
 }
+
+/**
+ * Restrict the config.php settings allowed.
+ *
+ * When running the behat features the config.php
+ * settings should not affect the results.
+ *
+ * @return void
+ */
+function behat_clean_init_config() {
+    global $CFG;
+
+    $allowed = array_flip(array(
+        'wwwroot', 'dataroot', 'dirroot', 'admin', 'directorypermissions', 'filepermissions',
+        'dbtype', 'dblibrary', 'dbhost', 'dbname', 'dbuser', 'dbpass', 'prefix', 'dboptions',
+        'proxyhost', 'proxyport', 'proxytype', 'proxyuser', 'proxypassword', 'proxybypass'
+    ));
+
+    // Also allowing behat_ prefixed attributes.
+    foreach ($CFG as $key => $value) {
+        if (!isset($allowed[$key]) && strpos($key, 'behat_') !== 0) {
+            unset($CFG->{$key});
+        }
+    }
+
+}
diff --git a/lib/setup.php b/lib/setup.php
index 0b9cbd2f40a..c776a891623 100644
--- a/lib/setup.php
+++ b/lib/setup.php
@@ -131,6 +131,10 @@ if (!defined('BEHAT_SITE_RUNNING') && !empty($CFG->behat_dataroot) &&
         // actions like reset the site or use data generators.
         define('BEHAT_SITE_RUNNING', true);
 
+        // Clean extra config.php settings.
+        require_once(__DIR__ . '/../lib/behat/lib.php');
+        behat_clean_init_config();
+
         $CFG->wwwroot = $CFG->behat_wwwroot;
         $CFG->passwordsaltmain = 'moodle';
         $CFG->prefix = $CFG->behat_prefix;