The Internet has matured to a mission-critical infrastructure, and recently attracted much attention at political and legal levels in many countries. Civil actions regarding the Internet infrastructure require a thorough understanding of the national components of the global Internet to foresee possible impacts of regulations and operations at a country-level. In this paper we report on a methodology, tool chain and results for identifying and classifying a 'national Internet'. We argue for the importance to consider individual IP-blocks and quantify the effects of our proposed approach. The methods have been applied to identify a 'German Internet', but are designed general enough to work for most countries, as well.