diff --git a/SMTPServer/SMTPServer.sln b/SMTPServer/SMTPServer.sln
index a907b9c..0591f69 100644
--- a/SMTPServer/SMTPServer.sln
+++ b/SMTPServer/SMTPServer.sln
@@ -5,6 +5,8 @@ VisualStudioVersion = 15.0.25914.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SMTPServer", "SMTPServer\SMTPServer.csproj", "{ABB6A3E6-38B6-4D02-AC9C-91FA69CF03BE}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{D43013F8-933F-4ADC-8943-08E91662A070}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
diff --git a/SMTPServer/SMTPServer/Exceptions/PortUsedException.cs b/SMTPServer/SMTPServer/Exceptions/PortUsedException.cs
new file mode 100644
index 0000000..ee405ba
--- /dev/null
+++ b/SMTPServer/SMTPServer/Exceptions/PortUsedException.cs
@@ -0,0 +1,22 @@
+using System;
+
+namespace SMTPServer.Exceptions
+{
+    public class PortUsedException : Exception
+    {
+        public PortUsedException() : base()
+        {
+
+        }
+
+        public PortUsedException(string message) : base(message)
+        {
+
+        }
+
+        public PortUsedException(string message, Exception inner) : base(message, inner)
+        {
+            
+        }
+    }
+}
\ No newline at end of file
diff --git a/SMTPServer/SMTPServer/PortListener.cs b/SMTPServer/SMTPServer/PortListener.cs
new file mode 100644
index 0000000..a85ffa5
--- /dev/null
+++ b/SMTPServer/SMTPServer/PortListener.cs
@@ -0,0 +1,64 @@
+using SMTPServer.Exceptions;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+
+namespace SMTPServer
+{
+    public delegate void ConnectedEventHandler(object source, ConnectedEventArgs e);
+
+    public class ConnectedEventArgs : EventArgs
+    {
+        private string EventInfo;
+
+        public Socket Client { get; private set; }
+
+        public ConnectedEventArgs(Socket client)
+        {
+            Client = client;
+        }
+    }
+
+    public class PortListener
+    {
+        static List<int> _Ports = null;
+        TcpListener _Listener;
+
+        public event ConnectedEventHandler OnConnected;
+
+        public PortListener(int port)
+        {
+            if(_Ports == null)
+            {
+                _Ports = new List<int>();
+            }
+
+            foreach(var i in _Ports)
+            {
+                if (i == port)
+                {
+                    throw new PortUsedException();
+                }
+            }
+
+            _Ports.Add(port);
+            StartListening(new TcpListener(IPAddress.Any, port));
+        }
+
+        private void StartListening(TcpListener listener)
+        {
+            listener.Start();
+            _Listener = listener;
+            Thread thread = new Thread(new ThreadStart(ListenerAsync));
+        }
+
+        private async void ListenerAsync()
+        {
+            var client = await _Listener.AcceptSocketAsync();
+            OnConnected(this, new ConnectedEventArgs(client));
+        }
+    }
+}
diff --git a/SMTPServer/SMTPServer/Program.cs b/SMTPServer/SMTPServer/Program.cs
index 104ecf0..85aea45 100644
--- a/SMTPServer/SMTPServer/Program.cs
+++ b/SMTPServer/SMTPServer/Program.cs
@@ -1,9 +1,20 @@
 using System;
 
-class Program
+namespace SMTPServer
 {
-    static void Main(string[] args)
+    class Program
     {
-        Console.WriteLine("Hello World!");
+        static void Main(string[] args)
+        {
+            Console.WriteLine("####################");
+
+            var listener = new PortListener(5122);
+            listener.OnConnected += Listener_OnConnected;
+        }
+
+        private static void Listener_OnConnected(object source, ConnectedEventArgs e)
+        {
+            throw new NotImplementedException();
+        }
     }
 }
\ No newline at end of file
diff --git a/SMTPServer/SMTPServer/SMTPServer.csproj b/SMTPServer/SMTPServer/SMTPServer.csproj
index 35c4d2b..fbb51e6 100644
--- a/SMTPServer/SMTPServer/SMTPServer.csproj
+++ b/SMTPServer/SMTPServer/SMTPServer.csproj
@@ -1,25 +1,24 @@
-<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" />
-  
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp1.0</TargetFramework>
   </PropertyGroup>
-
   <ItemGroup>
     <Compile Include="**\*.cs" />
     <EmbeddedResource Include="**\*.resx" />
   </ItemGroup>
-
+  <ItemGroup>
+    <Compile Include="PortListener.cs" />
+  </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.NETCore.App">
-      <Version>1.0.1</Version>
+      <Version>1.1.0</Version>
     </PackageReference>
     <PackageReference Include="Microsoft.NET.Sdk">
       <Version>1.0.0-alpha-20161104-2</Version>
       <PrivateAssets>All</PrivateAssets>
     </PackageReference>
   </ItemGroup>
-  
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
 </Project>
\ No newline at end of file
diff --git a/SMTPServer/SMTPServer/StartTcpConnection.cs b/SMTPServer/SMTPServer/StartTcpConnection.cs
new file mode 100644
index 0000000..b97b533
--- /dev/null
+++ b/SMTPServer/SMTPServer/StartTcpConnection.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Text;
+
+namespace SMTPServer
+{
+    class StartTcpConnection
+    {
+        public StartTcpConnection(int port, IPAddress destination)
+        {
+            
+        }
+
+    }
+}
diff --git a/SMTPServer/SMTPServer/TCPListener.cs b/SMTPServer/SMTPServer/TCPListener.cs
new file mode 100644
index 0000000..a1017ea
--- /dev/null
+++ b/SMTPServer/SMTPServer/TCPListener.cs
@@ -0,0 +1,64 @@
+using SMTPServer.Exceptions;
+using System;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+
+namespace SMTPServer
+{
+    public delegate void ConnectedEventHandler(object source, ConnectedEventArgs e);
+
+    public class ConnectedEventArgs : EventArgs
+    {
+        private string EventInfo;
+
+        public Socket Client { get; private set; }
+
+        public ConnectedEventArgs(Socket client)
+        {
+            Client = client;
+        }
+    }
+
+    public class TCPListener
+    {
+        static List<int> _Ports = null;
+        TcpListener _Listener;
+
+        public event ConnectedEventHandler OnConnected;
+
+        public TCPListener(int port)
+        {
+            if(_Ports == null)
+            {
+                _Ports = new List<int>();
+            }
+
+            foreach(var i in _Ports)
+            {
+                if (i == port)
+                {
+                    throw new PortUsedException();
+                }
+            }
+
+            _Ports.Add(port);
+            StartListening(new TcpListener(IPAddress.Any, port));
+        }
+
+        private void StartListening(TcpListener listener)
+        {
+            listener.Start();
+            _Listener = listener;
+            Thread thread = new Thread(new ThreadStart(ListenerAsync));
+        }
+
+        private async void ListenerAsync()
+        {
+            var client = await _Listener.AcceptSocketAsync();
+            OnConnected(this, new ConnectedEventArgs(client));
+        }
+    }
+}
diff --git a/SMTPServer/TCPListener.cs b/SMTPServer/TCPListener.cs
new file mode 100644
index 0000000..d555ecb
--- /dev/null
+++ b/SMTPServer/TCPListener.cs
@@ -0,0 +1,8 @@
+using System;
+
+public class Class1
+{
+	public Class1()
+	{
+	}
+}