thanks for your time 
and a pleasure for your replies. thks
I have got conexion with a external server, I read external files, and execute a query in a mysql via get, etc... but I don´t get it in localhost 
I have the mac of my arduino : 0x90, 0xA2, 0xDA, 0x0D, 0x69, 0xDB
I have got the arduino IP via Ethernet - Arduino Reference : IPAddress ip(192,168,1,33);
I have the IPv4 of my computer ( like you say with ipconfig ) : IPAddress server(192,168,1,34);
also I have a file http://127.0.0.1/arduino.txt ready for reading ( running WAMP)
if I use : IPAddress server(127,0,0,1); I get conexion, but I don´t read anything : I don´t found the file.
if I use : IPAddress server(192,168,1,1); I get conexion and i read the info of router
if I use : IPAddress server(192,168,1,34); I don´t make conexion