Discard the buffer if the protocol is unknown

src/main/java/org/jboss/netty/example/portunification/PortUnificationServerHandler.java

@@ -78,7 +78,8 @@ public class PortUnificationServerHandler extends FrameDecoder {
         } else if (isFactorial(magic1)) {
             switchToFactorial(ctx);
         } else {
-            // Unknown protocol
+            // Unknown protocol discard everything and close the connection.
+            buffer.skipBytes(buffer.readableBytes());
             ctx.getChannel().close();
             return null;
         }