Untitled

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace testMail
{
    class Program
    {
        static void Main(string[] args)
        {
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPAddress ipAdd = System.Net.IPAddress.Parse("192.168.1.198");
            IPEndPoint remoteEP = new IPEndPoint(ipAdd, 12345);

            var c = new Credentials() { user = "mail@mail3.edu", pwd = "1234" };
            var cmd = new Command() { serverCommand = 0, parameters = "my great parameters", credentials = c };
            string jsonString = JsonConvert.SerializeObject(cmd);


            socket.Connect(remoteEP);


            byte[] byData = System.Text.Encoding.ASCII.GetBytes(jsonString);
            socket.Send(byData);


            socket.Disconnect(false);
            socket.Close();
        }
    }

    [Serializable]
    public class Credentials
    {
        public string user { get; set; }
        public string pwd { get; set; }
    }

    [Serializable]
    public class Command
    {
        public int serverCommand { get; set; }
        public string parameters { get; set; }
        public Credentials credentials { get; set; }
    }
}