Netty Server connection with SSL drops client connection after invocation - sockets

Question

I am running Netty 4.2 socket communication code with ssl (self signed certificate).
My Problem:
When client tries to connect to server with SSL, server immediately drops the connection. Server triggers channelUnregistered() method immediately.
One point I noticed is, very first time once the server started, client connection holds and works fine. But when client disconnects and try to connect to Server again, it drops the connection immediately.
But without SSL it works fine without any issues.
Client Code:
public Channel initializeNettySocket()
{
group = new NioEventLoopGroup();
try
{
ClientAdapterInitializer clientAdapterInitializer = null;
if (ServerSettings.isUseSSL())
{
// SSLEngine engine = SSLContextFactory.getClientContext().createSSLEngine();
SSLEngine engine = SSLContext.getDefault().createSSLEngine(host,port);
engine.setUseClientMode(true);
clientAdapterInitializer = new ClientAdapterInitializer(engine);
}
else
{
clientAdapterInitializer = new ClientAdapterInitializer();
}
Bootstrap bootstrap = new Bootstrap().group(group).channel(NioSocketChannel.class).handler(clientAdapterInitializer);
channel = bootstrap.connect(host,port).sync().channel();
Thread.sleep(3000);
setChannel(channel);
}
catch (Exception e)
{
System.out.println(e.getMessage());
e.printStackTrace();
}
return channel;
}
public class ClientAdapterInitializer extends ChannelInitializer<SocketChannel>
{
private SSLEngine sslCtx = null;
public ClientAdapterInitializer(SSLEngine sslCtx)
{
this.sslCtx = sslCtx;
}
public ClientAdapterInitializer()
{
}
#Override
protected void initChannel(SocketChannel channel) throws Exception
{
ChannelPipeline pipeline = channel.pipeline();
if (ServerSettings.isUseSSL())
{
// Add SSL handler first to encrypt and decrypt everything.
// In this example, we use a bogus certificate in the server side
// and accept any invalid certificates in the client side.
// You will need something more complicated to identify both
// and server in the real world.
//pipeline.addLast(sslCtx.newHandler(ch.alloc(), SecureChatClient.HOST, SecureChatClient.PORT));
pipeline.addLast(new SslHandler(sslCtx));
}
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast("handler", new ClientAdapterHandler());
}
Server side code
public class ServerAdapterInitializer extends ChannelInitializer<SocketChannel>
{
private SSLEngine sslEngine;
public ServerAdapterInitializer(SSLEngine sslEngine)
{
this.sslEngine = sslEngine;
}
public ServerAdapterInitializer()
{
}
#Override
protected void initChannel(SocketChannel channel) throws Exception
{
ChannelPipeline pipeline = channel.pipeline();
if (sslEngine != null)
{
pipeline.addLast(new SslHandler(sslEngine));
}
Listeners.getInstance().getAllListeners().size();
RTReceiverAdapterHandler rtReceiverAdapterHandler = new RTReceiverAdapterHandler();
pipeline.addLast("idleStateHandler", new IdleStateHandler(0, 0, 10)); // add
// with
// name
pipeline.addLast("decoder", new MyStringDecoder(rtReceiverAdapterHandler));
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast("handler", rtReceiverAdapterHandler);
}
}
public class RTReceiverAdapterHandler extends ChannelInboundHandlerAdapter
{
#Override
public void channelActive(ChannelHandlerContext ctx) throws Exception
{
if (ServerSettings.isUseSSL())
{
// Once session is secured, send a greeting and register the channel
// to the global channel
// list so the channel received the messages from others.
ctx.pipeline().get(SslHandler.class).handshakeFuture().addListener(new GenericFutureListener<Future<Channel>>()
{
#Override
public void operationComplete(Future<Channel> future) throws Exception
{
ctx.writeAndFlush("Welcome!\n");
ctx.writeAndFlush("Your session is protected by " + ctx.pipeline().get(SslHandler.class).engine().getSession().getCipherSuite()
+ " cipher suite.\n");
channels.add(ctx.channel());
}
});
}
else
{
super.channelActive(ctx);
}
}
}

Answer 1

The problem was not with the code at all. We have nginx web server configured with SSL before my application. This entry in nginx 'ssl_ciphers AES256+EECDH:AES256+EDH:!aNULL;' was the culprit which was not allowing to access the netty server.
I commented the above entry in ngnix and my problem was resolved.