diff --git a/shadowsocks-csharp/Controller/Listener.cs b/shadowsocks-csharp/Controller/Listener.cs
new file mode 100755
index 00000000..923bc0e7
--- /dev/null
+++ b/shadowsocks-csharp/Controller/Listener.cs
@@ -0,0 +1,143 @@
+using Shadowsocks.Model;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+
+namespace Shadowsocks.Controller
+{
+    public class Listener
+    {
+        public interface Service
+        {
+            bool Handle(byte[] firstPacket, int length, Socket socket);
+        }
+
+        Configuration _config;
+        bool _shareOverLAN;
+        Socket _socket;
+        IList<Service> _services;
+
+        public Listener(IList<Service> services)
+        {
+            this._services = services;
+        }
+
+        public void Start(Configuration config)
+        {
+            this._config = config;
+            this._shareOverLAN = config.shareOverLan;
+            try
+            {
+                // Create a TCP/IP socket.
+                _socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+                _socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
+                IPEndPoint localEndPoint = null;
+                if (_shareOverLAN)
+                {
+                    localEndPoint = new IPEndPoint(IPAddress.Any, _config.localPort);
+                }
+                else
+                {
+                    localEndPoint = new IPEndPoint(IPAddress.Loopback, _config.localPort);
+                }
+
+                // Bind the socket to the local endpoint and listen for incoming connections.
+                _socket.Bind(localEndPoint);
+                _socket.Listen(1024);
+
+
+                // Start an asynchronous socket to listen for connections.
+                Console.WriteLine("Shadowsocks started");
+                _socket.BeginAccept(
+                    new AsyncCallback(AcceptCallback),
+                    _socket);
+            }
+            catch (SocketException)
+            {
+                _socket.Close();
+                throw;
+            }
+        }
+
+        public void Stop()
+        {
+            if (_socket != null)
+            {
+                _socket.Close();
+                _socket = null;
+            }
+        }
+
+        public void AcceptCallback(IAsyncResult ar)
+        {
+            Socket listener = (Socket)ar.AsyncState;
+            try
+            {
+                Socket conn = listener.EndAccept(ar);
+
+                byte[] buf = new byte[4096];
+                object[] state = new object[] {
+                    conn,
+                    buf
+                };
+
+                conn.BeginReceive(buf, 0, buf.Length, 0,
+                    new AsyncCallback(ReceiveCallback), state);
+            }
+            catch (ObjectDisposedException)
+            {
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine(e);
+            }
+            finally
+            {
+                try
+                {
+                    listener.BeginAccept(
+                        new AsyncCallback(AcceptCallback),
+                        listener);
+                }
+                catch (ObjectDisposedException)
+                {
+                    // do nothing
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                }
+            }
+        }
+
+
+        private void ReceiveCallback(IAsyncResult ar)
+        {
+            object[] state = (object[])ar.AsyncState;
+
+            Socket conn = (Socket)state[0];
+            byte[] buf = (byte[])state[1];
+            try
+            {
+                int bytesRead = conn.EndReceive(ar);
+                foreach (Service service in _services)
+                {
+                    if (service.Handle(buf, bytesRead, conn))
+                    {
+                        return;
+                    }
+                }
+                // no service found for this
+                // shouldn't happen
+                conn.Close();
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine(e);
+                conn.Close();
+            }
+        }
+    }
+}
diff --git a/shadowsocks-csharp/Controller/PortForwarder.cs b/shadowsocks-csharp/Controller/PortForwarder.cs
new file mode 100755
index 00000000..ce7d1048
--- /dev/null
+++ b/shadowsocks-csharp/Controller/PortForwarder.cs
@@ -0,0 +1,265 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+
+namespace Shadowsocks.Controller
+{
+    class PortForwarder : Listener.Service
+    {
+        int _targetPort;
+
+        public PortForwarder(int targetPort)
+        {
+            this._targetPort = targetPort;
+        }
+
+        public bool Handle(byte[] firstPacket, int length, Socket socket)
+        {
+            new Handler().Start(firstPacket, length, socket, this._targetPort);
+            return true;
+        }
+
+        class Handler
+        {
+            private byte[] _firstPacket;
+            private int _firstPacketLength;
+            private Socket _local;
+            private Socket _remote;
+            private bool _closed = false;
+            private bool _localShutdown = false;
+            private bool _remoteShutdown = false;
+            public const int RecvSize = 16384;
+            // remote receive buffer
+            private byte[] remoteRecvBuffer = new byte[RecvSize];
+            // connection receive buffer
+            private byte[] connetionRecvBuffer = new byte[RecvSize];
+
+            public void Start(byte[] firstPacket, int length, Socket socket, int targetPort)
+            {
+                this._firstPacket = firstPacket;
+                this._firstPacketLength = length;
+                this._local = socket;
+                try
+                {
+                    // TODO async resolving
+                    IPAddress ipAddress;
+                    bool parsed = IPAddress.TryParse("127.0.0.1", out ipAddress);
+                    IPEndPoint remoteEP = new IPEndPoint(ipAddress, targetPort);
+
+
+                    _remote = new Socket(ipAddress.AddressFamily,
+                        SocketType.Stream, ProtocolType.Tcp);
+                    _remote.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.NoDelay, true);
+
+                    // Connect to the remote endpoint.
+                    _remote.BeginConnect(remoteEP,
+                        new AsyncCallback(ConnectCallback), null);
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void ConnectCallback(IAsyncResult ar)
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    _remote.EndConnect(ar);
+                    HandshakeReceive();
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void HandshakeReceive()
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    _remote.BeginSend(_firstPacket, 0, _firstPacketLength, 0, new AsyncCallback(StartPipe), null);
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+
+            private void StartPipe(IAsyncResult ar)
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    _remote.EndSend(ar);
+                    _remote.BeginReceive(remoteRecvBuffer, 0, RecvSize, 0,
+                        new AsyncCallback(PipeRemoteReceiveCallback), null);
+                    _local.BeginReceive(connetionRecvBuffer, 0, RecvSize, 0,
+                        new AsyncCallback(PipeConnectionReceiveCallback), null);
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void PipeRemoteReceiveCallback(IAsyncResult ar)
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    int bytesRead = _remote.EndReceive(ar);
+
+                    if (bytesRead > 0)
+                    {
+                        int bytesToSend;
+                        _local.BeginSend(remoteRecvBuffer, 0, bytesRead, 0, new AsyncCallback(PipeConnectionSendCallback), null);
+                    }
+                    else
+                    {
+                        //Console.WriteLine("bytesRead: " + bytesRead.ToString());
+                        _local.Shutdown(SocketShutdown.Send);
+                        _localShutdown = true;
+                        CheckClose();
+                    }
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void PipeConnectionReceiveCallback(IAsyncResult ar)
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    int bytesRead = _local.EndReceive(ar);
+
+                    if (bytesRead > 0)
+                    {
+                        _remote.BeginSend(connetionRecvBuffer, 0, bytesRead, 0, new AsyncCallback(PipeRemoteSendCallback), null);
+                    }
+                    else
+                    {
+                        _remote.Shutdown(SocketShutdown.Send);
+                        _remoteShutdown = true;
+                        CheckClose();
+                    }
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void PipeRemoteSendCallback(IAsyncResult ar)
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    _remote.EndSend(ar);
+                    _local.BeginReceive(this.connetionRecvBuffer, 0, RecvSize, 0,
+                        new AsyncCallback(PipeConnectionReceiveCallback), null);
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void PipeConnectionSendCallback(IAsyncResult ar)
+            {
+                if (_closed)
+                {
+                    return;
+                }
+                try
+                {
+                    _local.EndSend(ar);
+                    _remote.BeginReceive(this.remoteRecvBuffer, 0, RecvSize, 0,
+                        new AsyncCallback(PipeRemoteReceiveCallback), null);
+                }
+                catch (Exception e)
+                {
+                    Logging.LogUsefulException(e);
+                    this.Close();
+                }
+            }
+
+            private void CheckClose()
+            {
+                if (_localShutdown && _remoteShutdown)
+                {
+                    this.Close();
+                }
+            }
+
+            public void Close()
+            {
+                lock (this)
+                {
+                    if (_closed)
+                    {
+                        return;
+                    }
+                    _closed = true;
+                }
+                if (_local != null)
+                {
+                    try
+                    {
+                        _local.Shutdown(SocketShutdown.Both);
+                        _local.Close();
+                    }
+                    catch (Exception e)
+                    {
+                        Logging.LogUsefulException(e);
+                    }
+                }
+                if (_remote != null)
+                {
+                    try
+                    {
+                        _remote.Shutdown(SocketShutdown.Both);
+                        _remote.Close();
+                    }
+                    catch (SocketException e)
+                    {
+                        Logging.LogUsefulException(e);
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/shadowsocks-csharp/Controller/ShadowsocksController.cs b/shadowsocks-csharp/Controller/ShadowsocksController.cs
index 06f04f61..fde74419 100755
--- a/shadowsocks-csharp/Controller/ShadowsocksController.cs
+++ b/shadowsocks-csharp/Controller/ShadowsocksController.cs
@@ -221,6 +221,7 @@ namespace Shadowsocks.Controller
                 List<Listener.Service> services = new List<Listener.Service>();
                 services.Add(local);
                 services.Add(_pacServer);
+                services.Add(new PortForwarder(8123));
                 _listener = new Listener(services);
                 _listener.Start(_config);
             }
diff --git a/shadowsocks-csharp/shadowsocks-csharp.csproj b/shadowsocks-csharp/shadowsocks-csharp.csproj
index e22a9fbd..3d51fabb 100755
--- a/shadowsocks-csharp/shadowsocks-csharp.csproj
+++ b/shadowsocks-csharp/shadowsocks-csharp.csproj
@@ -129,6 +129,7 @@
     <Compile Include="Controller\I18N.cs" />
     <Compile Include="Controller\Listener.cs" />
     <Compile Include="Controller\Logging.cs" />
+    <Compile Include="Controller\PortForwarder.cs" />
     <Compile Include="Controller\UpdateChecker.cs" />
     <Compile Include="Encryption\EncryptorBase.cs" />
     <Compile Include="Encryption\EncryptorFactory.cs" />