GPRS / Dynamic IP-Address range of the operators

[JWtheCoolOne]

Hello,

I developed a mobile service based on J2ME that communicates with a backend system. To avoid hack attacks on the backend system I would like to do IP-Address filtering. I want to limit the access to the ip-address range from the german operators. Does anybody know where to find the IP-address range of the mobile operators?

Best Regards,

Jan

[petrib]

RIPE (http://www.ripe.net/)? The mobile operator's (technical) customer service?