We live in a well-connected and technology dependent world. People, institutions, companies have increasing need for communication in everyday life. Global and seamless connectivity today is enabled by complex telecommunications infrastructure consisting of a large variety of different technologies which are in a continuous process of development and innovations. But, the global connectivity and easy access to modern technology also enables malicious users and their activities. These activities might be of a different nature: starting from passive monitoring to destructive attacks disabling the normal operation of ICT (information and communication technology) infrastructure. Therefore, security issues of the telecommunication infrastructure must be thoroughly addressed by all relevant stakeholders. Although each technology includes certain security mechanisms, it is necessary to create a well-designed security concept for the infrastructure as a whole, taking into consideration not only the technical issues, but also policy framework and legal aspects. The concept must be a subject of constant revision in order to be up to date to current threats. Therefore, the network infrastructure must be always monitored and analyzed, in order to create efficient measures against the security threats. The telecommunication infrastructure in the Republic of Macedonia is owned and operated by state institutions, telecom operators and providers, other companies and universities etc. All of them are faced with a number of malicious activities and attacks exploiting vulnerabilities of the systems, which are well monitored and statistically analyzed. Also, all of them have defined a more or less effective security concept including proactive and reactive measures. However, a common practice of cooperation and exchange of information and experience among the subjects is missing. A national strategy and policy framework are also missing that will benefit all stakeholders resulting in more effective and less expensive solutions as a response to cyber-attacks.