unit  _relayUnit1;
 //============================================================================== 
 interface 
 //============================================================================== 
 uses 
  Windows, Messages, SysUtils, Classes, Controls, Forms, IdBaseComponent,
  IdComponent, IdTCPServer, IdMappedPortTCP;
 //============================================================================== 
 type 
  TForm1 =  class (TForm)
    MyTCPMap: TIdMappedPortTCP;
     procedure  FormCreate(Sender: TObject);
     procedure  StartSocket;
   private 
     { Private declarations } 
   public 
     { Public declarations } 
   end ;
 //============================================================================== 
 var 
  Form1: TForm1;
 const 
  my_msg = 'USAGE: _tcprelay.exe <mapped host> <mapped port> <port>' + Chr( 13 ) + Chr( 10 ) + 'EXAMPLE: _relay.exe smtp.mail.ru 25 2550'  + Chr( 13 ) + Chr( 10 ) + 'EXAMPLE: _relay.exe 192.168.0.1 25 2550';
 //============================================================================== 
 implementation 
 //============================================================================== 
 {$R *.dfm} 
 //============================================================================== 
 procedure  TForm1.StartSocket;
   begin 
    MyTCPMap.Active := false;
       try 
        MyTCPMap.MappedHost := ParamStr( 1 );
        MyTCPMap.MappedPort := StrToInt(ParamStr( 2 ));
        MyTCPMap.DefaultPort := StrToInt(ParamStr( 3 ));
        MyTCPMap.Active := true;
       except 
        Application.MessageBox(PAnsiChar(my_msg),'_tcprelay', 0 );
       end ;
   end ;
 //============================================================================== 
 procedure  TForm1.FormCreate(Sender: TObject);
   begin 
     if  ParamCount <>  3   then 
       begin 
        Application.MessageBox(PAnsiChar(my_msg),'_tcprelay', 0 );
        ExitProcess( 0 );
       end ;
    StartSocket;
   end ;
 //============================================================================== 
 end .