Practical IPv6 monitoring-challenges and techniques

Network monitoring is an essential task of network management. Information obtained by monitoring devices gives a real picture of the network in production including transmitted data volumes, top hosts, a list of frequently used applications etc. Deep analysis of data collected by monitoring can reveal network attacks or detect misuse of network services. In addition, Data Retention Act requires each ISP to track user´s activities. Protocol IPv6 puts new challenges for network administrators in the context of user identification. Unlike IPv4, an IPv6 address no longer uniquely identifies a user or PC. IPv6 address can be randomly generated and keeps changing in time. PCs with IPv6 stack can also communicate via predefined tunnels over IPv4 infrastructure. That tunneled traffic mostly bypasses network security implemented via firewalls. In this paper, we identify major monitoring and security issues of IPv6 connectivity and propose a solution based on SNMP and Netflow data that helps to uniquely identify users. The solution requires an extended set of monitoring data to be collected from network devices. We present a new data structure based on extended Netflow records. Feasibility of the approach is demonstrated on the Brno University of Technology (BUT) campus network.