diff --git a/lib/Persistence/TrafficLimiter.php b/lib/Persistence/TrafficLimiter.php
index 168b46c..f5f8e7a 100644
--- a/lib/Persistence/TrafficLimiter.php
+++ b/lib/Persistence/TrafficLimiter.php
@@ -161,7 +161,7 @@ class TrafficLimiter extends AbstractPersistence
             }
         }
 
-        // this hash is used as an array key, hence a shorter algo is used
+        // used as array key, which are limited in length, hence using algo with shorter range
         $hash = self::getHash('sha256');
         $now  = time();
         $tl   = (int) self::$_store->getValue('traffic_limiter', $hash);
diff --git a/tst/Persistence/TrafficLimiterTest.php b/tst/Persistence/TrafficLimiterTest.php
index 8c83f0b..289598e 100644
--- a/tst/Persistence/TrafficLimiterTest.php
+++ b/tst/Persistence/TrafficLimiterTest.php
@@ -45,10 +45,14 @@ class TrafficLimiterTest extends PHPUnit_Framework_TestCase
         $this->assertTrue(TrafficLimiter::canPass(), 'fourth request has different ip and may pass');
         $_SERVER['REMOTE_ADDR'] = '127.0.0.1';
         $this->assertFalse(TrafficLimiter::canPass(), 'fifth request is to fast, may not pass');
+    }
 
-        // exempted IPs configuration
+    public function testTrafficLimitExempted()
+    {
         TrafficLimiter::setExempted('1.2.3.4,10.10.10.0/24,2001:1620:2057::/48');
-        $this->assertFalse(TrafficLimiter::canPass(), 'still too fast and not exempted');
+        $_SERVER['REMOTE_ADDR'] = '127.0.0.1';
+        $this->assertTrue(TrafficLimiter::canPass(), 'first request may pass');
+        $this->assertFalse(TrafficLimiter::canPass(), 'not exempted');
         $_SERVER['REMOTE_ADDR'] = '10.10.10.10';
         $this->assertTrue(TrafficLimiter::canPass(), 'IPv4 in exempted range');
         $this->assertTrue(TrafficLimiter::canPass(), 'request is to fast, but IPv4 in exempted range');
@@ -56,6 +60,7 @@ class TrafficLimiterTest extends PHPUnit_Framework_TestCase
         $this->assertTrue(TrafficLimiter::canPass(), 'IPv6 in exempted range');
         $this->assertTrue(TrafficLimiter::canPass(), 'request is to fast, but IPv6 in exempted range');
         TrafficLimiter::setExempted('127.*,foobar');
+        $this->assertTrue(TrafficLimiter::canPass(), 'first cached request may pass');
         $this->assertFalse(TrafficLimiter::canPass(), 'request is to fast, invalid range');
         $_SERVER['REMOTE_ADDR'] = 'foobar';
         $this->assertTrue(TrafficLimiter::canPass(), 'non-IP address');