IPv4 addresses are still running out. Global IPv4 address pool administered by IANA organization is depleted together with IPv4 pool of APNIC Routing Registry. This situation pushes organizations to think about IPv6 transition. Unfortunately IPv4 and IPv6 are incompatible protocols which raise new security issues and problems with user monitoring and accounting. The article shares experiences of deploying IPv6 on the university campus network and describes the most significant troubles that we have been faced with. It describes and compares differences in first hop security in IPv6 and IPv4 networks. Issues connected with user addressing, accounting and monitoring are also discussed. The experience is mainly based on the deployment of IPv6 on the campus network at Brno University of Technology which is one of the biggest universities in the Czech Republic.