This paper deals with interoperability and feature set testing process of all the currently available open-source EIGRP implementations. The network topology and the network address plan, together with all the virtualization tools used to create the topology is summarized. Then, all the necessary and notable EIGRP features tests are described and the results are shown in the form of console logs and packet captures. The reader is also presented with the brief overview of the EIGRP routing protocol itself, the history and notable features of the Quagga routing suite, and Quagga's fork Free Range Routing. The brief description of the OpenBSD EIGRP implementation is also included.