Hi everybody! I need a little bit of help, please. I'm working with Arduino UNO and GSM shield developed with Telefonica (http://arduino.cc/en/Main/ArduinoGSMShield). I used the example from Arduino (http://arduino.cc/en/Tutorial/GSMExamplesWebServer) in order to create a server that listens for requests. All worked fine with the code, but the statement IPAddress LocalIP = gprs.getIPAddress(); assigns an IP (given by the services provider) that is clear is changing. I need to do requests to this Arduino server to change some pin values when received, but the IP issue don't allow me to send the request to some fixed adress. So my question is : Is there any option to fix the IP adress or to make the request to the Arduino server with the IP changing every time? All your answers are welcome. I''l be glad with your feedback. Greetings from Mexico. 
I believe that you need to contact your service provider to get a static IP address.
Thank you for yor answer! But, Is there any other way to achieve it? The problem I had using other options is that, for example in the case of DNS or VPN, is that Arduino server would need to send request to the DNS OR VPN service or to install some kind of software. Am I in a wrong paradigm? If so, please correct me. Best regards.