diff --git a/core/src/main/java/org/apache/ftpserver/impl/PassivePorts.java b/core/src/main/java/org/apache/ftpserver/impl/PassivePorts.java
index f539540..19585ec 100644
--- a/core/src/main/java/org/apache/ftpserver/impl/PassivePorts.java
+++ b/core/src/main/java/org/apache/ftpserver/impl/PassivePorts.java
@@ -158,11 +158,11 @@
     }
 
     public PassivePorts(final int[] passivePorts, boolean checkIfBound) {
-        if (passivePorts != null) {
-            this.passivePorts = passivePorts.clone();
-        } else {
-            this.passivePorts = null;
-        }
+    	if(passivePorts == null) {
+    		throw new NullPointerException("passivePorts can not be null");
+    	}
+    	
+        this.passivePorts = passivePorts.clone();
 
         reservedPorts = new boolean[passivePorts.length];
         this.checkIfBound = checkIfBound;
diff --git a/core/src/test/java/org/apache/ftpserver/impl/PassivePortsTest.java b/core/src/test/java/org/apache/ftpserver/impl/PassivePortsTest.java
index 57021de..1167e20 100644
--- a/core/src/test/java/org/apache/ftpserver/impl/PassivePortsTest.java
+++ b/core/src/test/java/org/apache/ftpserver/impl/PassivePortsTest.java
@@ -203,4 +203,12 @@
         assertEquals(-1, ports.reserveNextPort());
     }
 
+    public void testNullPorts() {
+    	try {
+    		new PassivePorts((int[])null, false);
+    		fail("Must throw NPE");
+    	} catch(NullPointerException e) {
+    		// ok
+    	}
+    }
 }