GSM network capable of connecting to any operator providing SIP trunk has beenconstructed to serve as a target for controlled experiment on DoS attacks againstGSM. The usage of this network as a tool to perform DoS attack against mobilephones was also investigated and documented.Open source implementation of testing tool to check DoS resilience of any GSMbase station against RACH flood attack was developed as part of this thesis.Additionally, the analysis of the GSM flaws which opened the possibility for DoSattacks, and the analysis of potential countermeasures is presented.