This diploma thesis deals with the issue of attacks and fraud against mobile networks, with the main aim being implementation of a honeypot-type tool possessing the ability to respond to these accordingly. Thus, this thesis contains a basic introduction into mobile networks, their topology and commonly used protocols, along with analysis of their general security. This is followed by a clarification of the term honeypot itself, with an explanation of motivations for its deployment into the networks, together with listing of advantages and disadvantages such deployment may bring. The rest of the thesis deals with the actual implementation of such tool, specifically with its design, realisation and testing. This thesis presents a method for responding to the supported frauds, a detailed description of the implementation, configuration and outputs of the tool. The process of testing whether the implementation corresponds to the presented design is described here. The implemented tool is evaluated and its further possible improvements are discussed.