diff --git a/src/Client.php b/src/Client.php
index 2c608eeb3a..fae7521cb6 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -706,9 +706,10 @@ protected function openTempStream()
      */
     public function setAuth($user, $password, $type = self::AUTH_BASIC)
     {
-        if (!defined('self::AUTH_' . strtoupper($type))) {
+        if (!defined('static::AUTH_' . strtoupper($type))) {
             throw new Exception\InvalidArgumentException("Invalid or not supported authentication type: '$type'");
         }
+
         if (empty($user)) {
             throw new Exception\InvalidArgumentException("The username cannot be empty");
         }
@@ -717,7 +718,6 @@ public function setAuth($user, $password, $type = self::AUTH_BASIC)
             'user'     => $user,
             'password' => $password,
             'type'     => $type
-
         );
 
         return $this;
diff --git a/test/ClientTest.php b/test/ClientTest.php
index 4433ed7623..da22793267 100644
--- a/test/ClientTest.php
+++ b/test/ClientTest.php
@@ -18,6 +18,7 @@
 use Zend\Http\Request;
 use Zend\Http\Response;
 use Zend\Http\Client\Adapter\Test;
+use ZendTest\Http\TestAsset\ExtendedClient;
 
 
 class ClientTest extends \PHPUnit_Framework_TestCase
@@ -374,4 +375,24 @@ public function testPrepareHeadersCreateRightHttpField()
         $this->assertArrayNotHasKey('content-length', $headers);
         $this->assertArrayHasKey('Content-Length', $headers);
     }
+
+    /**
+     * @group 6301
+     */
+    public function testCanSpecifyCustomAuthMethodsInExtendingClasses()
+    {
+        $client = new ExtendedClient();
+
+        $client->setAuth('username', 'password', ExtendedClient::AUTH_CUSTOM);
+
+        $this->assertAttributeEquals(
+            array (
+                'user'     => 'username',
+                'password' => 'password',
+                'type'     => ExtendedClient::AUTH_CUSTOM,
+            ),
+            'auth',
+            $client
+        );
+    }
 }
diff --git a/test/TestAsset/ExtendedClient.php b/test/TestAsset/ExtendedClient.php
new file mode 100644
index 0000000000..170bef0e6e
--- /dev/null
+++ b/test/TestAsset/ExtendedClient.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace ZendTest\Http\TestAsset;
+
+use Zend\Http\Client;
+
+class ExtendedClient extends Client
+{
+    const AUTH_CUSTOM = 'custom';
+}