First developed to support cyber defense competitions (CDCs), ISERink is a virtual laboratory environment that allows students an opportunity to undertake hands-on activities focused on networking, cyber security and penetration testing. Each range consists of multiple subnets and can support dozens of teams. ISERink is also connected to the internet to allow users access to web servers. It is built on an internet testbed named ISEAGE that provides a real world networking environment for students. To the students it appears as if their network, which uses public address space, is directly connected to the internet. However, the students’ traffic is contained in the controlled ISEAGE testbed. This prevents misconfigurations or other beginner mistakes from disrupting a classroom or campus network.