The objective of this thesis is to present an implemented software module that provides IP address management in monitoring systems. Retrieving data from network devices by using Zabbix monitoring system provides a solution that includes planning, tracking, and assigning IP addresses in communication networks. The introduction chapter is subdivided into two parts. The first part defines the basic concepts whilst the second part provides an overview of the elaborated topics by chapter. The second chapter deals with the monitoring systems and how they communicate with network devices. The Zabbix monitoring system is explained further into details with an overview of the architecture and API that enables software extensions. The third chapter deals with the IP address management and explains principles of the IP addressing and tree aggregation of the subnets. The algorithm is presented that generates a list of the trees aggregating subnets from the set of IP addresses and corresponding network masks. The fourth chapter describes implemented software that integrates the Zabbix monitoring system and the IP address management methods. An overview is given of the architecture overview as well as the configuration of the Zabbix required for retrieving data. The retrieval and processing of the collected data needed for display are also described, and a user perspective overview of the implemented functionalities is given. Finally, in the fifth chapter presents the concluding thoughts of the author who sees the possibilities of the software extensions in communication networks and suggests further upgrades of the implemented solution.