diff --git a/DTLib.Network/DTLib.Network.csproj b/DTLib.Network/DTLib.Network.csproj
index 25c9a9a..1948be1 100644
--- a/DTLib.Network/DTLib.Network.csproj
+++ b/DTLib.Network/DTLib.Network.csproj
@@ -15,7 +15,7 @@
         <DebugType>embedded</DebugType>
         <!--language features-->
         <LangVersion>10</LangVersion>
-        <Nullable>disable</Nullable>
+        <Nullable>enable</Nullable>
         <ImplicitUsings>disable</ImplicitUsings>
     </PropertyGroup>
 
diff --git a/DTLib.Network/FSP2/Client.cs b/DTLib.Network/FSP2/Client.cs
new file mode 100644
index 0000000..b2ac795
--- /dev/null
+++ b/DTLib.Network/FSP2/Client.cs
@@ -0,0 +1,18 @@
+using System.Net;
+
+namespace DTLib.Network.FSP2;
+
+public class Client : IDisposable
+{
+    private TCPSocketClient _tcp;
+
+    public Client(IPEndPoint serverEndpoint)
+    {
+        _tcp = new TCPSocketClient(serverEndpoint);
+    }
+    
+    public void Dispose()
+    {
+        _tcp.Dispose();
+    }
+}
\ No newline at end of file
diff --git a/DTLib.Network/FSP2/Request.cs b/DTLib.Network/FSP2/Request.cs
new file mode 100644
index 0000000..a77788d
--- /dev/null
+++ b/DTLib.Network/FSP2/Request.cs
@@ -0,0 +1,13 @@
+namespace DTLib.Network.FSP2;
+
+public enum RequestType
+{
+    Message,
+    DownloadFile,
+    UploadFile
+}
+
+public record Request(RequestType Type)
+{
+    
+}
\ No newline at end of file
diff --git a/DTLib.Network/FSP2/Response.cs b/DTLib.Network/FSP2/Response.cs
new file mode 100644
index 0000000..48c20fd
--- /dev/null
+++ b/DTLib.Network/FSP2/Response.cs
@@ -0,0 +1,13 @@
+namespace DTLib.Network.FSP2;
+
+public enum ResponseStatus
+{
+    OK,
+    InvalidRequest,
+    AccessDenied
+}
+
+public record Response(ResponseStatus Status)
+{ 
+    
+}
\ No newline at end of file
diff --git a/DTLib.Network/FSP2/Server.cs b/DTLib.Network/FSP2/Server.cs
new file mode 100644
index 0000000..666e4d6
--- /dev/null
+++ b/DTLib.Network/FSP2/Server.cs
@@ -0,0 +1,26 @@
+using System.Net;
+
+namespace DTLib.Network.FSP2;
+
+public class Server : IDisposable
+{
+    
+    private TCPSocketServer _tcp;
+    private readonly Func<Request, Response> _requestHandler;
+    
+    public Server(IPEndPoint localEndpoint, Func<Request, Response> requestHandler, Action<Exception> exceptionHandler)
+    {
+        _requestHandler = requestHandler;
+        _tcp = new TCPSocketServer(localEndpoint, HandleFSP2Connection, exceptionHandler);
+    }
+
+    void HandleFSP2Connection(TCPSocketServer.ConnectionParams p)
+    {
+        
+    }
+    
+    public void Dispose()
+    {
+        _tcp.Dispose();
+    }
+}
\ No newline at end of file
diff --git a/DTLib.Network/Functions.cs b/DTLib.Network/Functions.cs
new file mode 100644
index 0000000..7dab119
--- /dev/null
+++ b/DTLib.Network/Functions.cs
@@ -0,0 +1,19 @@
+global using System.Net.Sockets;
+global using System;
+global using System.Threading;
+global using System.Collections.Generic;
+global using System.Linq;
+global using System.Text;
+global using DTLib.Extensions;
+global using DTLib.Filesystem;
+global using static DTLib.Logging.InternalLog;
+using System.Diagnostics;
+using System.Net.Http;
+
+namespace DTLib.Network;
+
+public static class Functions
+{
+    /// gets public ip of this machine from ifconfig.me
+    public static string GetPublicIP() => new HttpClient().GetStringAsync("https://ifconfig.me/ip").GetAwaiter().GetResult();
+}
diff --git a/DTLib.Network/OldNetwork.cs b/DTLib.Network/OldNetwork.cs
deleted file mode 100644
index 06aa6b8..0000000
--- a/DTLib.Network/OldNetwork.cs
+++ /dev/null
@@ -1,41 +0,0 @@
-global using System.Net.Sockets;
-global using System;
-global using System.Threading;
-global using System.Collections.Generic;
-global using System.Linq;
-global using System.Text;
-global using DTLib.Extensions;
-global using DTLib.Filesystem;
-global using static DTLib.Logging.InternalLog;
-using System.Diagnostics;
-using System.Net.Http;
-
-namespace DTLib.Network;
-
-// 
-// пара почти никогда не используемых методов
-//
-public static class OldNetwork
-{
-
-
-    // получает с сайта публичный ip
-    public static string GetPublicIP() => new HttpClient().GetStringAsync("https://ifconfig.me/ip").GetAwaiter().GetResult();
-
-    // пингует айпи с помощью встроенной в винду проги, возвращает задержку
-    public static string PingIP(string address)
-    {
-        var proc = new Process();
-        proc.StartInfo.FileName = "cmd.exe";
-        proc.StartInfo.Arguments = "/c @echo off & chcp 65001 >nul & ping -n 5 " + address;
-        proc.StartInfo.CreateNoWindow = true;
-        proc.StartInfo.UseShellExecute = false;
-        proc.StartInfo.RedirectStandardOutput = true;
-        proc.Start();
-        System.IO.StreamReader outStream = proc.StandardOutput;
-        string rezult = outStream.ReadToEnd();
-        rezult = rezult.Remove(0, rezult.LastIndexOf('=') + 2);
-        return rezult.Remove(rezult.Length - 4);
-    }
-
-}
diff --git a/DTLib.Network/TCPSocketClient.cs b/DTLib.Network/TCPSocketClient.cs
new file mode 100644
index 0000000..511ede9
--- /dev/null
+++ b/DTLib.Network/TCPSocketClient.cs
@@ -0,0 +1,45 @@
+using System.Net;
+
+namespace DTLib.Network;
+
+public class TCPSocketClient : IDisposable
+{
+    protected Socket? _mainSocket;
+    public readonly IPEndPoint ServerEndpoint;
+    
+    public TCPSocketClient(IPEndPoint serverEndpoint)
+    {
+        ServerEndpoint = serverEndpoint;
+    }
+
+    public virtual void Connect()
+    {
+        _mainSocket = new(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+        _mainSocket.Connect(ServerEndpoint);
+    }
+
+    public virtual void Stop()
+    {
+        if(_mainSocket is null)
+            return;
+        _mainSocket.Shutdown(SocketShutdown.Both);
+        _mainSocket.Close();
+        _mainSocket = null;
+    }
+
+    public void Dispose() => Stop();
+
+    public void Send(byte[] buffer)
+    {
+        if (_mainSocket is null)
+            throw new NullReferenceException("TCP socket is null! You have to call Connect() befure calling Send()");
+        _mainSocket.Send(buffer);
+    }
+
+    public int Recieve(ref byte[] buffer)
+    {
+        if (_mainSocket is null)
+            throw new NullReferenceException("TCP socket is null! You have to call Connect() befure calling Recieve()");
+        _mainSocket.Receive(buffer);
+    }
+}
\ No newline at end of file
diff --git a/DTLib.Network/TCPSocketServer.cs b/DTLib.Network/TCPSocketServer.cs
new file mode 100644
index 0000000..b09852a
--- /dev/null
+++ b/DTLib.Network/TCPSocketServer.cs
@@ -0,0 +1,101 @@
+using System.Net;
+
+namespace DTLib.Network;
+
+/// <summary>
+/// Multi-threaded TCP
+/// </summary>
+public class TCPSocketServer : IDisposable
+{
+    public readonly IPEndPoint LocalEndPoint;
+    
+    public record ConnectionParams(Socket ConnectionSocket, Thread ConnectionThread);
+    
+    protected Action<ConnectionParams>? _connectionHandler;
+    protected Action<Exception> _exceptionCallback;
+    protected Socket? _mainSocket;
+
+    /// <param name="localEndpoint">address and port of the server in the local network</param>
+    /// <param name="incomingConnectionHandler">this delegate is called on every incoming socket connection</param>
+    /// <param name="exceptionCallback">this delegate is called on every Exception throwed in threads created by the server</param>
+    public TCPSocketServer(IPEndPoint localEndpoint,
+        Action<ConnectionParams>? incomingConnectionHandler,
+        Action<Exception> exceptionCallback)
+    {
+        LocalEndPoint = localEndpoint;
+        _connectionHandler = incomingConnectionHandler;
+        _exceptionCallback = exceptionCallback;
+    }
+
+    private volatile int acceptLoopRunning = 0;
+    
+    /// <summary>
+    /// Starts server on a new thread
+    /// </summary>
+    /// <exception cref="Exception">the server is already started</exception>
+    public virtual void Listen()
+    {
+        if (Interlocked.CompareExchange(ref acceptLoopRunning, 1, 1) == 1)
+            throw new Exception("Server is already started. Stop it to ");
+        
+        _mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+        _mainSocket.Bind(LocalEndPoint);
+        _mainSocket.Listen(64);
+        Thread loopThread = new Thread(AcceptLoop);
+        loopThread.Start();
+    }
+
+    /// server runs this loop in special thread
+    private void AcceptLoop()
+    {
+        try
+        {
+            // atomic (thread-safe) comparison acceptLoopRunning==1
+            while (Interlocked.CompareExchange(ref acceptLoopRunning, 1, 1) == 1)
+            {
+                Socket incomingConnection = _mainSocket!.Accept();
+                Thread connectionThread = new Thread(HandleConnection);
+                connectionThread.Start(new ConnectionParams(incomingConnection, connectionThread));
+            }
+        }
+        catch (Exception e)
+        {
+            _exceptionCallback(e); 
+            Stop();
+        }
+    }
+
+
+    private void HandleConnection(object? _p)
+    {
+        var p = (ConnectionParams)_p!;
+        try
+        {
+            _connectionHandler?.Invoke(p);
+        }
+        catch (Exception e)
+        {
+            _exceptionCallback(e);
+        }
+        finally
+        {
+            p.ConnectionSocket.Shutdown(SocketShutdown.Both);
+            p.ConnectionSocket.Close();
+        }
+    }
+    
+    public virtual void Stop()
+    {
+        // atomic (thread-safe) comparison acceptLoopRunning==0 and assignement acceptLoopRunning=0
+        if (Interlocked.CompareExchange(ref acceptLoopRunning, 0, 1) == 0)
+            throw new Exception("Server isn't running");
+        
+        if(_mainSocket is null)
+            return;
+        
+        _mainSocket.Shutdown(SocketShutdown.Both);
+        _mainSocket.Close();
+    }
+    
+    public void Dispose() => Stop();
+}
\ No newline at end of file