22. Chaos Communication Congress 3G Investigations lecture slides Scanning your GPRS/UMTS IP network for fun and profit We are giving an overview of ip networks used for >=2.5G technologies. Our main focus is on scanning the overlaying ip network, on different Voice-over-IP filter implementations and the possibilities to circumvent them. We want to explain the ip networks used in GPRS and UMTS cellular networks from the enduser point of view. How do they work today and what has to be done to get a normal webpage, voice-over-ip or even a video stream onto your PDA or SmartPhone. For your private investigations inside your providers ip network we want to demonstrate you a tcp/udp port and round-trip-time based traceroute program based on the .NET compact framework. With the help of this program we want to analyse the anti voice-over-ip filters implemented by different cellular providers and show you some possibilities how to circumvent them _efficently_. So we don't just tunnel all the traffic through a VPN. But even when these filters become more sophisticated in the future we want to present some ideas how to defeat your right to talk via voice-over-ip whereever and whenever you want to. Here are the slides of our lecture.