Chat-like TCP communication problem

Question

Wel... Ive been working on a chat application for a week now and Im desperate right now...

the thing is that my application works on LAN but it doesnt work through internet. When i use my local IP the connection is made but when I get my IP from whatsmyip.com and use it there are numerous problems...

here's the server:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Threading;

namespace TCPChatServer
{
    class Program
    {
        public static TcpListener tcpListener;
        public static int port;
        public static IPAddress ip;
        public static TcpClient tcpClient;

        static void Main()
        {
            GetMyIP.get();
            ip = GetMyIP.ip;
            ip = IPAddress.Parse("93.139.3.97");
            port = 15555;
            tcpListener = new TcpListener(IPAddress.Any,port);

// so. when i use IPAddress.Any it doesnt get through and when i use my ip i get error: The requested address is not valid in its context
// and when i use my local ip (192.168.1.4) everything works fine... im out of ideas...

            tcpListener.Start();

            tcpClient = tcpListener.AcceptTcpClient();

            NetworkStream netStream = tcpClient.GetStream();
            Byte[] message = new Byte[1000];
            int bytesRead;

            bytesRead = netStream.Read(message, 0, 100);

            string sms = ASCIIEncoding.ASCII.GetString(message);
            Console.WriteLine(sms);

            Console.WriteLine("end");
            Console.Read();

        }
    }
}

and here's the "client":
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Threading;

namespace SimpleChatClient
{
    class Program
    {

        static void Main()
        {
            int trace = 0;

            TcpClient client = new TcpClient();

                                                                  // 93.139.3.97 192.168.1.4
            IPEndPoint serverEndPoint = new IPEndPoint(IPAddress.Parse("93.139.3.97"), 15555);
            Console.WriteLine(trace++);
            client.Connect(IPAddress.Parse("93.139.3.97"), 15555);

            Console.WriteLine(trace++);
            NetworkStream clientStream = client.GetStream();

            Console.WriteLine(trace++);
            ASCIIEncoding encoder = new ASCIIEncoding();
            byte[] buffer = encoder.GetBytes("Hello Server!");

            Console.WriteLine(trace++);
            clientStream.Write(buffer, 0, buffer.Length);
            Console.WriteLine(trace++);
            
            clientStream.Flush();


        }
    }
}