The IETF has developed a network configuration management protocol called NETCONF which was published as proposed standard in 2006. The NETCONF protocol provides mechanisms to install, manipulate, and delete the configuration of network devices by using an Extensible Markup Language (XML) based data encoding on top of a simple Remote Procedure Call (RPC) layer. This report describes a NETCONF interoperability testing plan that is used to test whether NETCONF protocol implementations meet the NETCONF protocol specification. The test of three independent NETCONF implementations reveals bugs in several NETCONF implementations. While constructing test cases, a few shortcomings of the specifications were identified as well.