diff --git a/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java b/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
index 6628bb2..099880d 100644
--- a/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
+++ b/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
@@ -200,12 +200,12 @@
 
     @Override
     public void registerHandler(String type, MessageHandler handler) {
-        handlers.putIfAbsent(type, handler);
+        handlers.put(type, handler);
     }
 
     @Override
     public void registerHandler(String type, MessageHandler handler, ExecutorService executor) {
-        handlers.putIfAbsent(type, new MessageHandler() {
+        handlers.put(type, new MessageHandler() {
             @Override
             public void handle(Message message) throws IOException {
                 executor.submit(() -> {