An extract from this http://rakaperbawa.blogspot.de/2013/11/installing-openimscore-with-ipv6.html
This OpenIMSCore came with standard capability to provide SIP service such as VoIP and video call. So you don’t need to install the Application Service for these type of services. Originally, this IMS concept was designed to be worked on a full IPV6-based network, it means the addresses of the clients, the servers and the IMS itself have to be defined in IPv6. But in OpenIMSCore, the standard installation only came with IPV4 implementation, there’s several configuration have to be added later if we want to make our IMS work on IPV6.
So this is the tutorial, enjoy 😀